Move \OC\DB to PSR-4

Besides the statement wrapper that is moved to the legacy folder
(namepsace of shame folder)

30 files changed, 4451 insertions, 0 deletions

diff --git a/lib/private/DB/Adapter.php b/lib/private/DB/Adapter.php
new file mode 100644
index 00000000000..9522f768c88
--- /dev/null
+++ b/lib/private/DB/Adapter.php
@@ -0,0 +1,95 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Jonny007-MKD <1-23-4-5@web.de>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+/**
+ * This handles the way we use to write queries, into something that can be
+ * handled by the database abstraction layer.
+ */
+class Adapter {
+
+	/**
+	 * @var \OC\DB\Connection $conn
+	 */
+	protected $conn;
+
+	public function __construct($conn) {
+		$this->conn = $conn;
+	}
+
+	/**
+	 * @param string $table name
+	 * @return int id of last insert statement
+	 */
+	public function lastInsertId($table) {
+		return $this->conn->realLastInsertId($table);
+	}
+
+	/**
+	 * @param string $statement that needs to be changed so the db can handle it
+	 * @return string changed statement
+	 */
+	public function fixupStatement($statement) {
+		return $statement;
+	}
+
+	/**
+	 * Insert a row if the matching row does not exists.
+	 *
+	 * @param string $table The table name (will replace *PREFIX* with the actual prefix)
+	 * @param array $input data that should be inserted into the table  (column name => value)
+	 * @param array|null $compare List of values that should be checked for "if not exists"
+	 *				If this is null or an empty array, all keys of $input will be compared
+	 *				Please note: text fields (clob) must not be used in the compare array
+	 * @return int number of inserted rows
+	 * @throws \Doctrine\DBAL\DBALException
+	 */
+	public function insertIfNotExist($table, $input, array $compare = null) {
+		if (empty($compare)) {
+			$compare = array_keys($input);
+		}
+		$query = 'INSERT INTO `' .$table . '` (`'
+			. implode('`,`', array_keys($input)) . '`) SELECT '
+			. str_repeat('?,', count($input)-1).'? ' // Is there a prettier alternative?
+			. 'FROM `' . $table . '` WHERE ';
+
+		$inserts = array_values($input);
+		foreach($compare as $key) {
+			$query .= '`' . $key . '`';
+			if (is_null($input[$key])) {
+				$query .= ' IS NULL AND ';
+			} else {
+				$inserts[] = $input[$key];
+				$query .= ' = ? AND ';
+			}
+		}
+		$query = substr($query, 0, strlen($query) - 5);
+		$query .= ' HAVING COUNT(*) = 0';
+
+		return $this->conn->executeUpdate($query, $inserts);
+	}
+}
diff --git a/lib/private/DB/AdapterMySQL.php b/lib/private/DB/AdapterMySQL.php
new file mode 100644
index 00000000000..ab87c589747
--- /dev/null
+++ b/lib/private/DB/AdapterMySQL.php
@@ -0,0 +1,31 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+
+namespace OC\DB;
+
+class AdapterMySQL extends Adapter {
+	public function fixupStatement($statement) {
+		$statement = str_replace(' ILIKE ', ' COLLATE utf8_general_ci LIKE ', $statement);
+		return $statement;
+	}
+}
diff --git a/lib/private/DB/AdapterOCI8.php b/lib/private/DB/AdapterOCI8.php
new file mode 100644
index 00000000000..970d3eefa4d
--- /dev/null
+++ b/lib/private/DB/AdapterOCI8.php
@@ -0,0 +1,50 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+
+namespace OC\DB;
+
+class AdapterOCI8 extends Adapter {
+	public function lastInsertId($table) {
+		if (is_null($table)) {
+			throw new \InvalidArgumentException('Oracle requires a table name to be passed into lastInsertId()');
+		}
+		if ($table !== null) {
+			$suffix = '_SEQ';
+			$table = '"' . $table . $suffix . '"';
+		}
+		return $this->conn->realLastInsertId($table);
+	}
+
+	const UNIX_TIMESTAMP_REPLACEMENT = "(cast(sys_extract_utc(systimestamp) as date) - date'1970-01-01') * 86400";
+
+	public function fixupStatement($statement) {
+		$statement = preg_replace('( LIKE \?)', '$0 ESCAPE \'\\\'', $statement);
+		$statement = preg_replace('/`(\w+)` ILIKE \?/', 'REGEXP_LIKE(`$1`, \'^\' || REPLACE(?, \'%\', \'.*\') || \'$\', \'i\')', $statement);
+		$statement = str_replace('`', '"', $statement);
+		$statement = str_ireplace('NOW()', 'CURRENT_TIMESTAMP', $statement);
+		$statement = str_ireplace('UNIX_TIMESTAMP()', self::UNIX_TIMESTAMP_REPLACEMENT, $statement);
+		return $statement;
+	}
+}
diff --git a/lib/private/DB/AdapterPgSql.php b/lib/private/DB/AdapterPgSql.php
new file mode 100644
index 00000000000..a7d9377a0bf
--- /dev/null
+++ b/lib/private/DB/AdapterPgSql.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+
+namespace OC\DB;
+
+class AdapterPgSql extends Adapter {
+	public function lastInsertId($table) {
+		return $this->conn->fetchColumn('SELECT lastval()');
+	}
+
+	const UNIX_TIMESTAMP_REPLACEMENT = 'cast(extract(epoch from current_timestamp) as integer)';
+	public function fixupStatement($statement) {
+		$statement = str_replace( '`', '"', $statement );
+		$statement = str_ireplace( 'UNIX_TIMESTAMP()', self::UNIX_TIMESTAMP_REPLACEMENT, $statement );
+		return $statement;
+	}
+}
diff --git a/lib/private/DB/AdapterSqlite.php b/lib/private/DB/AdapterSqlite.php
new file mode 100644
index 00000000000..d7769238abc
--- /dev/null
+++ b/lib/private/DB/AdapterSqlite.php
@@ -0,0 +1,74 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+
+namespace OC\DB;
+
+class AdapterSqlite extends Adapter {
+	public function fixupStatement($statement) {
+		$statement = preg_replace('( I?LIKE \?)', '$0 ESCAPE \'\\\'', $statement);
+		$statement = preg_replace('/`(\w+)` ILIKE \?/', 'LOWER($1) LIKE LOWER(?)', $statement);
+		$statement = str_replace( '`', '"', $statement );
+		$statement = str_ireplace( 'NOW()', 'datetime(\'now\')', $statement );
+		$statement = str_ireplace( 'UNIX_TIMESTAMP()', 'strftime(\'%s\',\'now\')', $statement );
+		return $statement;
+	}
+
+	/**
+	 * Insert a row if the matching row does not exists.
+	 *
+	 * @param string $table The table name (will replace *PREFIX* with the actual prefix)
+	 * @param array $input data that should be inserted into the table  (column name => value)
+	 * @param array|null $compare List of values that should be checked for "if not exists"
+	 *				If this is null or an empty array, all keys of $input will be compared
+	 *				Please note: text fields (clob) must not be used in the compare array
+	 * @return int number of inserted rows
+	 * @throws \Doctrine\DBAL\DBALException
+	 */
+	public function insertIfNotExist($table, $input, array $compare = null) {
+		if (empty($compare)) {
+			$compare = array_keys($input);
+		}
+		$fieldList = '`' . implode('`,`', array_keys($input)) . '`';
+		$query = "INSERT INTO `$table` ($fieldList) SELECT "
+			. str_repeat('?,', count($input)-1).'? '
+			. " WHERE NOT EXISTS (SELECT 1 FROM `$table` WHERE ";
+
+		$inserts = array_values($input);
+		foreach($compare as $key) {
+			$query .= '`' . $key . '`';
+			if (is_null($input[$key])) {
+				$query .= ' IS NULL AND ';
+			} else {
+				$inserts[] = $input[$key];
+				$query .= ' = ? AND ';
+			}
+		}
+		$query = substr($query, 0, strlen($query) - 5);
+		$query .= ')';
+
+		return $this->conn->executeUpdate($query, $inserts);
+	}
+}
diff --git a/lib/private/DB/Connection.php b/lib/private/DB/Connection.php
new file mode 100644
index 00000000000..7904fab0726
--- /dev/null
+++ b/lib/private/DB/Connection.php
@@ -0,0 +1,373 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Robin McCorkell <robin@mccorkell.me.uk>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+use Doctrine\DBAL\DBALException;
+use Doctrine\DBAL\Driver;
+use Doctrine\DBAL\Configuration;
+use Doctrine\DBAL\Cache\QueryCacheProfile;
+use Doctrine\Common\EventManager;
+use OC\DB\QueryBuilder\QueryBuilder;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IDBConnection;
+use OCP\PreconditionNotMetException;
+
+class Connection extends \Doctrine\DBAL\Connection implements IDBConnection {
+	/**
+	 * @var string $tablePrefix
+	 */
+	protected $tablePrefix;
+
+	/**
+	 * @var \OC\DB\Adapter $adapter
+	 */
+	protected $adapter;
+
+	public function connect() {
+		try {
+			return parent::connect();
+		} catch (DBALException $e) {
+			// throw a new exception to prevent leaking info from the stacktrace
+			throw new DBALException('Failed to connect to the database: ' . $e->getMessage(), $e->getCode());
+		}
+	}
+
+	/**
+	 * Returns a QueryBuilder for the connection.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder
+	 */
+	public function getQueryBuilder() {
+		return new QueryBuilder($this);
+	}
+
+	/**
+	 * Gets the QueryBuilder for the connection.
+	 *
+	 * @return \Doctrine\DBAL\Query\QueryBuilder
+	 * @deprecated please use $this->getQueryBuilder() instead
+	 */
+	public function createQueryBuilder() {
+		$backtrace = $this->getCallerBacktrace();
+		\OC::$server->getLogger()->debug('Doctrine QueryBuilder retrieved in {backtrace}', ['app' => 'core', 'backtrace' => $backtrace]);
+		return parent::createQueryBuilder();
+	}
+
+	/**
+	 * Gets the ExpressionBuilder for the connection.
+	 *
+	 * @return \Doctrine\DBAL\Query\Expression\ExpressionBuilder
+	 * @deprecated please use $this->getQueryBuilder()->expr() instead
+	 */
+	public function getExpressionBuilder() {
+		$backtrace = $this->getCallerBacktrace();
+		\OC::$server->getLogger()->debug('Doctrine ExpressionBuilder retrieved in {backtrace}', ['app' => 'core', 'backtrace' => $backtrace]);
+		return parent::getExpressionBuilder();
+	}
+
+	/**
+	 * Get the file and line that called the method where `getCallerBacktrace()` was used
+	 *
+	 * @return string
+	 */
+	protected function getCallerBacktrace() {
+		$traces = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);
+
+		// 0 is the method where we use `getCallerBacktrace`
+		// 1 is the target method which uses the method we want to log
+		if (isset($traces[1])) {
+			return $traces[1]['file'] . ':' . $traces[1]['line'];
+		}
+
+		return '';
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getPrefix() {
+		return $this->tablePrefix;
+	}
+
+	/**
+	 * Initializes a new instance of the Connection class.
+	 *
+	 * @param array $params  The connection parameters.
+	 * @param \Doctrine\DBAL\Driver $driver
+	 * @param \Doctrine\DBAL\Configuration $config
+	 * @param \Doctrine\Common\EventManager $eventManager
+	 * @throws \Exception
+	 */
+	public function __construct(array $params, Driver $driver, Configuration $config = null,
+		EventManager $eventManager = null)
+	{
+		if (!isset($params['adapter'])) {
+			throw new \Exception('adapter not set');
+		}
+		if (!isset($params['tablePrefix'])) {
+			throw new \Exception('tablePrefix not set');
+		}
+		parent::__construct($params, $driver, $config, $eventManager);
+		$this->adapter = new $params['adapter']($this);
+		$this->tablePrefix = $params['tablePrefix'];
+
+		parent::setTransactionIsolation(parent::TRANSACTION_READ_COMMITTED);
+	}
+
+	/**
+	 * Prepares an SQL statement.
+	 *
+	 * @param string $statement The SQL statement to prepare.
+	 * @param int $limit
+	 * @param int $offset
+	 * @return \Doctrine\DBAL\Driver\Statement The prepared statement.
+	 */
+	public function prepare( $statement, $limit=null, $offset=null ) {
+		if ($limit === -1) {
+			$limit = null;
+		}
+		if (!is_null($limit)) {
+			$platform = $this->getDatabasePlatform();
+			$statement = $platform->modifyLimitQuery($statement, $limit, $offset);
+		}
+		$statement = $this->replaceTablePrefix($statement);
+		$statement = $this->adapter->fixupStatement($statement);
+
+		if(\OC::$server->getSystemConfig()->getValue( 'log_query', false)) {
+			\OCP\Util::writeLog('core', 'DB prepare : '.$statement, \OCP\Util::DEBUG);
+		}
+		return parent::prepare($statement);
+	}
+
+	/**
+	 * Executes an, optionally parametrized, SQL query.
+	 *
+	 * If the query is parametrized, a prepared statement is used.
+	 * If an SQLLogger is configured, the execution is logged.
+	 *
+	 * @param string                                      $query  The SQL query to execute.
+	 * @param array                                       $params The parameters to bind to the query, if any.
+	 * @param array                                       $types  The types the previous parameters are in.
+	 * @param \Doctrine\DBAL\Cache\QueryCacheProfile|null $qcp    The query cache profile, optional.
+	 *
+	 * @return \Doctrine\DBAL\Driver\Statement The executed statement.
+	 *
+	 * @throws \Doctrine\DBAL\DBALException
+	 */
+	public function executeQuery($query, array $params = array(), $types = array(), QueryCacheProfile $qcp = null)
+	{
+		$query = $this->replaceTablePrefix($query);
+		$query = $this->adapter->fixupStatement($query);
+		return parent::executeQuery($query, $params, $types, $qcp);
+	}
+
+	/**
+	 * Executes an SQL INSERT/UPDATE/DELETE query with the given parameters
+	 * and returns the number of affected rows.
+	 *
+	 * This method supports PDO binding types as well as DBAL mapping types.
+	 *
+	 * @param string $query  The SQL query.
+	 * @param array  $params The query parameters.
+	 * @param array  $types  The parameter types.
+	 *
+	 * @return integer The number of affected rows.
+	 *
+	 * @throws \Doctrine\DBAL\DBALException
+	 */
+	public function executeUpdate($query, array $params = array(), array $types = array())
+	{
+		$query = $this->replaceTablePrefix($query);
+		$query = $this->adapter->fixupStatement($query);
+		return parent::executeUpdate($query, $params, $types);
+	}
+
+	/**
+	 * Returns the ID of the last inserted row, or the last value from a sequence object,
+	 * depending on the underlying driver.
+	 *
+	 * Note: This method may not return a meaningful or consistent result across different drivers,
+	 * because the underlying database may not even support the notion of AUTO_INCREMENT/IDENTITY
+	 * columns or sequences.
+	 *
+	 * @param string $seqName Name of the sequence object from which the ID should be returned.
+	 * @return string A string representation of the last inserted ID.
+	 */
+	public function lastInsertId($seqName = null) {
+		if ($seqName) {
+			$seqName = $this->replaceTablePrefix($seqName);
+		}
+		return $this->adapter->lastInsertId($seqName);
+	}
+
+	// internal use
+	public function realLastInsertId($seqName = null) {
+		return parent::lastInsertId($seqName);
+	}
+
+	/**
+	 * Insert a row if the matching row does not exists.
+	 *
+	 * @param string $table The table name (will replace *PREFIX* with the actual prefix)
+	 * @param array $input data that should be inserted into the table  (column name => value)
+	 * @param array|null $compare List of values that should be checked for "if not exists"
+	 *				If this is null or an empty array, all keys of $input will be compared
+	 *				Please note: text fields (clob) must not be used in the compare array
+	 * @return int number of inserted rows
+	 * @throws \Doctrine\DBAL\DBALException
+	 */
+	public function insertIfNotExist($table, $input, array $compare = null) {
+		return $this->adapter->insertIfNotExist($table, $input, $compare);
+	}
+
+	private function getType($value) {
+		if (is_bool($value)) {
+			return IQueryBuilder::PARAM_BOOL;
+		} else if (is_int($value)) {
+			return IQueryBuilder::PARAM_INT;
+		} else {
+			return IQueryBuilder::PARAM_STR;
+		}
+	}
+
+	/**
+	 * Insert or update a row value
+	 *
+	 * @param string $table
+	 * @param array $keys (column name => value)
+	 * @param array $values (column name => value)
+	 * @param array $updatePreconditionValues ensure values match preconditions (column name => value)
+	 * @return int number of new rows
+	 * @throws \Doctrine\DBAL\DBALException
+	 * @throws PreconditionNotMetException
+	 */
+	public function setValues($table, array $keys, array $values, array $updatePreconditionValues = []) {
+		try {
+			$insertQb = $this->getQueryBuilder();
+			$insertQb->insert($table)
+				->values(
+					array_map(function($value) use ($insertQb) {
+						return $insertQb->createNamedParameter($value, $this->getType($value));
+					}, array_merge($keys, $values))
+				);
+			return $insertQb->execute();
+		} catch (\Doctrine\DBAL\Exception\ConstraintViolationException $e) {
+			// value already exists, try update
+			$updateQb = $this->getQueryBuilder();
+			$updateQb->update($table);
+			foreach ($values as $name => $value) {
+				$updateQb->set($name, $updateQb->createNamedParameter($value, $this->getType($value)));
+			}
+			$where = $updateQb->expr()->andx();
+			$whereValues = array_merge($keys, $updatePreconditionValues);
+			foreach ($whereValues as $name => $value) {
+				$where->add($updateQb->expr()->eq(
+					$name,
+					$updateQb->createNamedParameter($value, $this->getType($value)),
+					$this->getType($value)
+				));
+			}
+			$updateQb->where($where);
+			$affected = $updateQb->execute();
+
+			if ($affected === 0 && !empty($updatePreconditionValues)) {
+				throw new PreconditionNotMetException();
+			}
+
+			return 0;
+		}
+	}
+
+	/**
+	 * returns the error code and message as a string for logging
+	 * works with DoctrineException
+	 * @return string
+	 */
+	public function getError() {
+		$msg = $this->errorCode() . ': ';
+		$errorInfo = $this->errorInfo();
+		if (is_array($errorInfo)) {
+			$msg .= 'SQLSTATE = '.$errorInfo[0] . ', ';
+			$msg .= 'Driver Code = '.$errorInfo[1] . ', ';
+			$msg .= 'Driver Message = '.$errorInfo[2];
+		}
+		return $msg;
+	}
+
+	/**
+	 * Drop a table from the database if it exists
+	 *
+	 * @param string $table table name without the prefix
+	 */
+	public function dropTable($table) {
+		$table = $this->tablePrefix . trim($table);
+		$schema = $this->getSchemaManager();
+		if($schema->tablesExist(array($table))) {
+			$schema->dropTable($table);
+		}
+	}
+
+	/**
+	 * Check if a table exists
+	 *
+	 * @param string $table table name without the prefix
+	 * @return bool
+	 */
+	public function tableExists($table){
+		$table = $this->tablePrefix . trim($table);
+		$schema = $this->getSchemaManager();
+		return $schema->tablesExist(array($table));
+	}
+
+	// internal use
+	/**
+	 * @param string $statement
+	 * @return string
+	 */
+	protected function replaceTablePrefix($statement) {
+		return str_replace( '*PREFIX*', $this->tablePrefix, $statement );
+	}
+
+	/**
+	 * Check if a transaction is active
+	 *
+	 * @return bool
+	 * @since 8.2.0
+	 */
+	public function inTransaction() {
+		return $this->getTransactionNestingLevel() > 0;
+	}
+
+	/**
+	 * Espace a parameter to be used in a LIKE query
+	 *
+	 * @param string $param
+	 * @return string
+	 */
+	public function escapeLikeParameter($param) {
+		return addcslashes($param, '\\_%');
+	}
+}
diff --git a/lib/private/DB/ConnectionFactory.php b/lib/private/DB/ConnectionFactory.php
new file mode 100644
index 00000000000..0856d8d19c0
--- /dev/null
+++ b/lib/private/DB/ConnectionFactory.php
@@ -0,0 +1,184 @@
+<?php
+/**
+ * @author Andreas Fischer <bantu@owncloud.com>
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+use Doctrine\DBAL\Event\Listeners\OracleSessionInit;
+use Doctrine\DBAL\Event\Listeners\SQLSessionInit;
+use Doctrine\DBAL\Event\Listeners\MysqlSessionInit;
+
+/**
+* Takes care of creating and configuring Doctrine connections.
+*/
+class ConnectionFactory {
+	/**
+	* @var array
+	*
+	* Array mapping DBMS type to default connection parameters passed to
+	* \Doctrine\DBAL\DriverManager::getConnection().
+	*/
+	protected $defaultConnectionParams = array(
+		'mysql' => array(
+			'adapter' => '\OC\DB\AdapterMySQL',
+			'charset' => 'UTF8',
+			'driver' => 'pdo_mysql',
+			'wrapperClass' => 'OC\DB\Connection',
+		),
+		'oci' => array(
+			'adapter' => '\OC\DB\AdapterOCI8',
+			'charset' => 'AL32UTF8',
+			'driver' => 'oci8',
+			'wrapperClass' => 'OC\DB\OracleConnection',
+		),
+		'pgsql' => array(
+			'adapter' => '\OC\DB\AdapterPgSql',
+			'driver' => 'pdo_pgsql',
+			'wrapperClass' => 'OC\DB\Connection',
+		),
+		'sqlite3' => array(
+			'adapter' => '\OC\DB\AdapterSqlite',
+			'driver' => 'pdo_sqlite',
+			'wrapperClass' => 'OC\DB\Connection',
+		),
+	);
+
+	/**
+	* @brief Get default connection parameters for a given DBMS.
+	* @param string $type DBMS type
+	* @throws \InvalidArgumentException If $type is invalid
+	* @return array Default connection parameters.
+	*/
+	public function getDefaultConnectionParams($type) {
+		$normalizedType = $this->normalizeType($type);
+		if (!isset($this->defaultConnectionParams[$normalizedType])) {
+			throw new \InvalidArgumentException("Unsupported type: $type");
+		}
+		$result = $this->defaultConnectionParams[$normalizedType];
+		// \PDO::MYSQL_ATTR_FOUND_ROWS may not be defined, e.g. when the MySQL
+		// driver is missing. In this case, we won't be able to connect anyway.
+		if ($normalizedType === 'mysql' && defined('\PDO::MYSQL_ATTR_FOUND_ROWS')) {
+			$result['driverOptions'] = array(
+				\PDO::MYSQL_ATTR_FOUND_ROWS => true,
+			);
+		}
+		return $result;
+	}
+
+	/**
+	* @brief Get default connection parameters for a given DBMS.
+	* @param string $type DBMS type
+	* @param array $additionalConnectionParams Additional connection parameters
+	* @return \OC\DB\Connection
+	*/
+	public function getConnection($type, $additionalConnectionParams) {
+		$normalizedType = $this->normalizeType($type);
+		$eventManager = new \Doctrine\Common\EventManager();
+		switch ($normalizedType) {
+			case 'mysql':
+				// Send "SET NAMES utf8". Only required on PHP 5.3 below 5.3.6.
+				// See http://stackoverflow.com/questions/4361459/php-pdo-charset-set-names#4361485
+				$eventManager->addEventSubscriber(new MysqlSessionInit);
+				$eventManager->addEventSubscriber(
+					new SQLSessionInit("SET SESSION AUTOCOMMIT=1"));
+				break;
+			case 'oci':
+				$eventManager->addEventSubscriber(new OracleSessionInit);
+				break;
+			case 'sqlite3':
+				$journalMode = $additionalConnectionParams['sqlite.journal_mode'];
+				$additionalConnectionParams['platform'] = new OCSqlitePlatform();
+				$eventManager->addEventSubscriber(new SQLiteSessionInit(true, $journalMode));
+				break;
+		}
+		$connection = \Doctrine\DBAL\DriverManager::getConnection(
+			array_merge($this->getDefaultConnectionParams($type), $additionalConnectionParams),
+			new \Doctrine\DBAL\Configuration(),
+			$eventManager
+		);
+		return $connection;
+	}
+
+	/**
+	* @brief Normalize DBMS type
+	* @param string $type DBMS type
+	* @return string Normalized DBMS type
+	*/
+	public function normalizeType($type) {
+		return $type === 'sqlite' ? 'sqlite3' : $type;
+	}
+
+	/**
+	* @brief Checks whether the specified DBMS type is valid.
+	* @return bool
+	*/
+	public function isValidType($type) {
+		$normalizedType = $this->normalizeType($type);
+		return isset($this->defaultConnectionParams[$normalizedType]);
+	}
+
+	/**
+	 * Create the connection parameters for the config
+	 *
+	 * @param \OC\SystemConfig $config
+	 * @return array
+	 */
+	public function createConnectionParams($config) {
+		$type = $config->getValue('dbtype', 'sqlite');
+
+		$connectionParams = array(
+			'user' => $config->getValue('dbuser', ''),
+			'password' => $config->getValue('dbpassword', ''),
+		);
+		$name = $config->getValue('dbname', 'owncloud');
+
+		if ($this->normalizeType($type) === 'sqlite3') {
+			$dataDir = $config->getValue("datadirectory", \OC::$SERVERROOT . '/data');
+			$connectionParams['path'] = $dataDir . '/' . $name . '.db';
+		} else {
+			$host = $config->getValue('dbhost', '');
+			if (strpos($host, ':')) {
+				// Host variable may carry a port or socket.
+				list($host, $portOrSocket) = explode(':', $host, 2);
+				if (ctype_digit($portOrSocket)) {
+					$connectionParams['port'] = $portOrSocket;
+				} else {
+					$connectionParams['unix_socket'] = $portOrSocket;
+				}
+			}
+			$connectionParams['host'] = $host;
+			$connectionParams['dbname'] = $name;
+		}
+
+		$connectionParams['tablePrefix'] = $config->getValue('dbtableprefix', 'oc_');
+		$connectionParams['sqlite.journal_mode'] = $config->getValue('sqlite.journal_mode', 'WAL');
+
+		//additional driver options, eg. for mysql ssl
+		$driverOptions = $config->getValue('dbdriveroptions', null);
+		if ($driverOptions) {
+			$connectionParams['driverOptions'] = $driverOptions;
+		}
+
+		return $connectionParams;
+	}
+}
diff --git a/lib/private/DB/MDB2SchemaManager.php b/lib/private/DB/MDB2SchemaManager.php
new file mode 100644
index 00000000000..f73f6b4351a
--- /dev/null
+++ b/lib/private/DB/MDB2SchemaManager.php
@@ -0,0 +1,178 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
+ * @author Lukas Reschke <lukas@owncloud.com>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Roeland Jago Douma <rullzer@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Platforms\MySqlPlatform;
+use Doctrine\DBAL\Platforms\OraclePlatform;
+use Doctrine\DBAL\Platforms\PostgreSqlPlatform;
+use Doctrine\DBAL\Platforms\SqlitePlatform;
+use OCP\IDBConnection;
+
+class MDB2SchemaManager {
+	/** @var \OC\DB\Connection $conn */
+	protected $conn;
+
+	/**
+	 * @param IDBConnection $conn
+	 */
+	public function __construct($conn) {
+		$this->conn = $conn;
+	}
+
+	/**
+	 * saves database scheme to xml file
+	 * @param string $file name of file
+	 * @return bool
+	 *
+	 * TODO: write more documentation
+	 */
+	public function getDbStructure($file) {
+		return \OC\DB\MDB2SchemaWriter::saveSchemaToFile($file, $this->conn);
+	}
+
+	/**
+	 * Creates tables from XML file
+	 * @param string $file file to read structure from
+	 * @return bool
+	 *
+	 * TODO: write more documentation
+	 */
+	public function createDbFromStructure($file) {
+		$schemaReader = new MDB2SchemaReader(\OC::$server->getConfig(), $this->conn->getDatabasePlatform());
+		$toSchema = $schemaReader->loadSchemaFromFile($file);
+		return $this->executeSchemaChange($toSchema);
+	}
+
+	/**
+	 * @return \OC\DB\Migrator
+	 */
+	public function getMigrator() {
+		$random = \OC::$server->getSecureRandom();
+		$platform = $this->conn->getDatabasePlatform();
+		$config = \OC::$server->getConfig();
+		$dispatcher = \OC::$server->getEventDispatcher();
+		if ($platform instanceof SqlitePlatform) {
+			return new SQLiteMigrator($this->conn, $random, $config, $dispatcher);
+		} else if ($platform instanceof OraclePlatform) {
+			return new OracleMigrator($this->conn, $random, $config, $dispatcher);
+		} else if ($platform instanceof MySqlPlatform) {
+			return new MySQLMigrator($this->conn, $random, $config, $dispatcher);
+		} else if ($platform instanceof PostgreSqlPlatform) {
+			return new Migrator($this->conn, $random, $config, $dispatcher);
+		} else {
+			return new NoCheckMigrator($this->conn, $random, $config, $dispatcher);
+		}
+	}
+
+	/**
+	 * Reads database schema from file
+	 *
+	 * @param string $file file to read from
+	 * @return \Doctrine\DBAL\Schema\Schema
+	 */
+	private function readSchemaFromFile($file) {
+		$platform = $this->conn->getDatabasePlatform();
+		$schemaReader = new MDB2SchemaReader(\OC::$server->getConfig(), $platform);
+		return $schemaReader->loadSchemaFromFile($file);
+	}
+
+	/**
+	 * update the database scheme
+	 * @param string $file file to read structure from
+	 * @param bool $generateSql only return the sql needed for the upgrade
+	 * @return string|boolean
+	 */
+	public function updateDbFromStructure($file, $generateSql = false) {
+		$toSchema = $this->readSchemaFromFile($file);
+		$migrator = $this->getMigrator();
+
+		if ($generateSql) {
+			return $migrator->generateChangeScript($toSchema);
+		} else {
+			$migrator->migrate($toSchema);
+			return true;
+		}
+	}
+
+	/**
+	 * update the database scheme
+	 * @param string $file file to read structure from
+	 * @return boolean
+	 */
+	public function simulateUpdateDbFromStructure($file) {
+		$toSchema = $this->readSchemaFromFile($file);
+		$this->getMigrator()->checkMigrate($toSchema);
+		return true;
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $schema
+	 * @return string
+	 */
+	public function generateChangeScript($schema) {
+		$migrator = $this->getMigrator();
+		return $migrator->generateChangeScript($schema);
+	}
+
+	/**
+	 * remove all tables defined in a database structure xml file
+	 *
+	 * @param string $file the xml file describing the tables
+	 */
+	public function removeDBStructure($file) {
+		$schemaReader = new MDB2SchemaReader(\OC::$server->getConfig(), $this->conn->getDatabasePlatform());
+		$fromSchema = $schemaReader->loadSchemaFromFile($file);
+		$toSchema = clone $fromSchema;
+		/** @var $table \Doctrine\DBAL\Schema\Table */
+		foreach ($toSchema->getTables() as $table) {
+			$toSchema->dropTable($table->getName());
+		}
+		$comparator = new \Doctrine\DBAL\Schema\Comparator();
+		$schemaDiff = $comparator->compare($fromSchema, $toSchema);
+		$this->executeSchemaChange($schemaDiff);
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema|\Doctrine\DBAL\Schema\SchemaDiff $schema
+	 * @return bool
+	 */
+	private function executeSchemaChange($schema) {
+		$this->conn->beginTransaction();
+		foreach ($schema->toSql($this->conn->getDatabasePlatform()) as $sql) {
+			$this->conn->query($sql);
+		}
+		$this->conn->commit();
+
+		if ($this->conn->getDatabasePlatform() instanceof SqlitePlatform) {
+			$this->conn->close();
+			$this->conn->connect();
+		}
+		return true;
+	}
+}
diff --git a/lib/private/DB/MDB2SchemaReader.php b/lib/private/DB/MDB2SchemaReader.php
new file mode 100644
index 00000000000..375fec185cb
--- /dev/null
+++ b/lib/private/DB/MDB2SchemaReader.php
@@ -0,0 +1,359 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Oliver Gasser <oliver.gasser@gmail.com>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Robin McCorkell <robin@mccorkell.me.uk>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ * @author Victor Dubiniuk <dubiniuk@owncloud.com>
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Platforms\AbstractPlatform;
+use Doctrine\DBAL\Schema\SchemaConfig;
+use OCP\IConfig;
+
+class MDB2SchemaReader {
+	/**
+	 * @var string $DBNAME
+	 */
+	protected $DBNAME;
+
+	/**
+	 * @var string $DBTABLEPREFIX
+	 */
+	protected $DBTABLEPREFIX;
+
+	/**
+	 * @var \Doctrine\DBAL\Platforms\AbstractPlatform $platform
+	 */
+	protected $platform;
+
+	/** @var \Doctrine\DBAL\Schema\SchemaConfig $schemaConfig */
+	protected $schemaConfig;
+
+	/**
+	 * @param \OCP\IConfig $config
+	 * @param \Doctrine\DBAL\Platforms\AbstractPlatform $platform
+	 */
+	public function __construct(IConfig $config, AbstractPlatform $platform) {
+		$this->platform = $platform;
+		$this->DBNAME = $config->getSystemValue('dbname', 'owncloud');
+		$this->DBTABLEPREFIX = $config->getSystemValue('dbtableprefix', 'oc_');
+
+		// Oracle does not support longer index names then 30 characters.
+		// We use this limit for all DBs to make sure it does not cause a
+		// problem.
+		$this->schemaConfig = new SchemaConfig();
+		$this->schemaConfig->setMaxIdentifierLength(30);
+	}
+
+	/**
+	 * @param string $file
+	 * @return \Doctrine\DBAL\Schema\Schema
+	 * @throws \DomainException
+	 */
+	public function loadSchemaFromFile($file) {
+		$schema = new \Doctrine\DBAL\Schema\Schema();
+		$loadEntities = libxml_disable_entity_loader(false);
+		$xml = simplexml_load_file($file);
+		libxml_disable_entity_loader($loadEntities);
+		foreach ($xml->children() as $child) {
+			/**
+			 * @var \SimpleXMLElement $child
+			 */
+			switch ($child->getName()) {
+				case 'name':
+				case 'create':
+				case 'overwrite':
+				case 'charset':
+					break;
+				case 'table':
+					$this->loadTable($schema, $child);
+					break;
+				default:
+					throw new \DomainException('Unknown element: ' . $child->getName());
+
+			}
+		}
+		return $schema;
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $schema
+	 * @param \SimpleXMLElement $xml
+	 * @throws \DomainException
+	 */
+	private function loadTable($schema, $xml) {
+		$table = null;
+		foreach ($xml->children() as $child) {
+			/**
+			 * @var \SimpleXMLElement $child
+			 */
+			switch ($child->getName()) {
+				case 'name':
+					$name = (string)$child;
+					$name = str_replace('*dbprefix*', $this->DBTABLEPREFIX, $name);
+					$name = $this->platform->quoteIdentifier($name);
+					$table = $schema->createTable($name);
+					$table->addOption('collate', 'utf8_bin');
+					$table->setSchemaConfig($this->schemaConfig);
+					break;
+				case 'create':
+				case 'overwrite':
+				case 'charset':
+					break;
+				case 'declaration':
+					if (is_null($table)) {
+						throw new \DomainException('Table declaration before table name');
+					}
+					$this->loadDeclaration($table, $child);
+					break;
+				default:
+					throw new \DomainException('Unknown element: ' . $child->getName());
+
+			}
+		}
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Table $table
+	 * @param \SimpleXMLElement $xml
+	 * @throws \DomainException
+	 */
+	private function loadDeclaration($table, $xml) {
+		foreach ($xml->children() as $child) {
+			/**
+			 * @var \SimpleXMLElement $child
+			 */
+			switch ($child->getName()) {
+				case 'field':
+					$this->loadField($table, $child);
+					break;
+				case 'index':
+					$this->loadIndex($table, $child);
+					break;
+				default:
+					throw new \DomainException('Unknown element: ' . $child->getName());
+
+			}
+		}
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Table $table
+	 * @param \SimpleXMLElement $xml
+	 * @throws \DomainException
+	 */
+	private function loadField($table, $xml) {
+		$options = array( 'notnull' => false );
+		foreach ($xml->children() as $child) {
+			/**
+			 * @var \SimpleXMLElement $child
+			 */
+			switch ($child->getName()) {
+				case 'name':
+					$name = (string)$child;
+					$name = $this->platform->quoteIdentifier($name);
+					break;
+				case 'type':
+					$type = (string)$child;
+					switch ($type) {
+						case 'text':
+							$type = 'string';
+							break;
+						case 'clob':
+							$type = 'text';
+							break;
+						case 'timestamp':
+							$type = 'datetime';
+							break;
+						case 'numeric':
+							$type = 'decimal';
+							break;
+					}
+					break;
+				case 'length':
+					$length = (string)$child;
+					$options['length'] = $length;
+					break;
+				case 'unsigned':
+					$unsigned = $this->asBool($child);
+					$options['unsigned'] = $unsigned;
+					break;
+				case 'notnull':
+					$notnull = $this->asBool($child);
+					$options['notnull'] = $notnull;
+					break;
+				case 'autoincrement':
+					$autoincrement = $this->asBool($child);
+					$options['autoincrement'] = $autoincrement;
+					break;
+				case 'default':
+					$default = (string)$child;
+					$options['default'] = $default;
+					break;
+				case 'comments':
+					$comment = (string)$child;
+					$options['comment'] = $comment;
+					break;
+				case 'primary':
+					$primary = $this->asBool($child);
+					$options['primary'] = $primary;
+					break;
+				case 'precision':
+					$precision = (string)$child;
+					$options['precision'] = $precision;
+					break;
+				case 'scale':
+					$scale = (string)$child;
+					$options['scale'] = $scale;
+					break;
+				default:
+					throw new \DomainException('Unknown element: ' . $child->getName());
+
+			}
+		}
+		if (isset($name) && isset($type)) {
+			if (isset($options['default']) && empty($options['default'])) {
+				if (empty($options['notnull']) || !$options['notnull']) {
+					unset($options['default']);
+					$options['notnull'] = false;
+				} else {
+					$options['default'] = '';
+				}
+				if ($type == 'integer' || $type == 'decimal') {
+					$options['default'] = 0;
+				} elseif ($type == 'boolean') {
+					$options['default'] = false;
+				}
+				if (!empty($options['autoincrement']) && $options['autoincrement']) {
+					unset($options['default']);
+				}
+			}
+			if ($type === 'integer' && isset($options['default'])) {
+				$options['default'] = (int)$options['default'];
+			}
+			if ($type === 'integer' && isset($options['length'])) {
+				$length = $options['length'];
+				if ($length < 4) {
+					$type = 'smallint';
+				} else if ($length > 4) {
+					$type = 'bigint';
+				}
+			}
+			if ($type === 'boolean' && isset($options['default'])) {
+				$options['default'] = $this->asBool($options['default']);
+			}
+			if (!empty($options['autoincrement'])
+				&& !empty($options['notnull'])
+			) {
+				$options['primary'] = true;
+			}
+			$table->addColumn($name, $type, $options);
+			if (!empty($options['primary']) && $options['primary']) {
+				$table->setPrimaryKey(array($name));
+			}
+		}
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Table $table
+	 * @param \SimpleXMLElement $xml
+	 * @throws \DomainException
+	 */
+	private function loadIndex($table, $xml) {
+		$name = null;
+		$fields = array();
+		foreach ($xml->children() as $child) {
+			/**
+			 * @var \SimpleXMLElement $child
+			 */
+			switch ($child->getName()) {
+				case 'name':
+					$name = (string)$child;
+					break;
+				case 'primary':
+					$primary = $this->asBool($child);
+					break;
+				case 'unique':
+					$unique = $this->asBool($child);
+					break;
+				case 'field':
+					foreach ($child->children() as $field) {
+						/**
+						 * @var \SimpleXMLElement $field
+						 */
+						switch ($field->getName()) {
+							case 'name':
+								$field_name = (string)$field;
+								$field_name = $this->platform->quoteIdentifier($field_name);
+								$fields[] = $field_name;
+								break;
+							case 'sorting':
+								break;
+							default:
+								throw new \DomainException('Unknown element: ' . $field->getName());
+
+						}
+					}
+					break;
+				default:
+					throw new \DomainException('Unknown element: ' . $child->getName());
+
+			}
+		}
+		if (!empty($fields)) {
+			if (isset($primary) && $primary) {
+				if ($table->hasPrimaryKey()) {
+					return;
+				}
+				$table->setPrimaryKey($fields, $name);
+			} else {
+				if (isset($unique) && $unique) {
+					$table->addUniqueIndex($fields, $name);
+				} else {
+					$table->addIndex($fields, $name);
+				}
+			}
+		} else {
+			throw new \DomainException('Empty index definition: ' . $name . ' options:' . print_r($fields, true));
+		}
+	}
+
+	/**
+	 * @param \SimpleXMLElement|string $xml
+	 * @return bool
+	 */
+	private function asBool($xml) {
+		$result = (string)$xml;
+		if ($result == 'true') {
+			$result = true;
+		} elseif ($result == 'false') {
+			$result = false;
+		}
+		return (bool)$result;
+	}
+
+}
diff --git a/lib/private/DB/MDB2SchemaWriter.php b/lib/private/DB/MDB2SchemaWriter.php
new file mode 100644
index 00000000000..7dc3bd223a7
--- /dev/null
+++ b/lib/private/DB/MDB2SchemaWriter.php
@@ -0,0 +1,178 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author tbelau666 <thomas.belau@gmx.de>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Schema\Column;
+use Doctrine\DBAL\Schema\Index;
+
+class MDB2SchemaWriter {
+
+	/**
+	 * @param string $file
+	 * @param \OC\DB\Connection $conn
+	 * @return bool
+	 */
+	static public function saveSchemaToFile($file, \OC\DB\Connection $conn) {
+		$config = \OC::$server->getConfig();
+
+		$xml = new \SimpleXMLElement('<database/>');
+		$xml->addChild('name', $config->getSystemValue('dbname', 'owncloud'));
+		$xml->addChild('create', 'true');
+		$xml->addChild('overwrite', 'false');
+		$xml->addChild('charset', 'utf8');
+
+		// FIX ME: bloody work around
+		if ($config->getSystemValue('dbtype', 'sqlite') === 'oci') {
+			$filterExpression = '/^"' . preg_quote($conn->getPrefix()) . '/';
+		} else {
+			$filterExpression = '/^' . preg_quote($conn->getPrefix()) . '/';
+		}
+		$conn->getConfiguration()->setFilterSchemaAssetsExpression($filterExpression);
+
+		foreach ($conn->getSchemaManager()->listTables() as $table) {
+			self::saveTable($table, $xml->addChild('table'));
+		}
+		file_put_contents($file, $xml->asXML());
+		return true;
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Table $table
+	 * @param \SimpleXMLElement $xml
+	 */
+	private static function saveTable($table, $xml) {
+		$xml->addChild('name', $table->getName());
+		$declaration = $xml->addChild('declaration');
+		foreach($table->getColumns() as $column) {
+			self::saveColumn($column, $declaration->addChild('field'));
+		}
+		foreach($table->getIndexes() as $index) {
+			if ($index->getName() == 'PRIMARY') {
+				$autoincrement = false;
+				foreach($index->getColumns() as $column) {
+					if ($table->getColumn($column)->getAutoincrement()) {
+						$autoincrement = true;
+					}
+				}
+				if ($autoincrement) {
+					continue;
+				}
+			}
+			self::saveIndex($index, $declaration->addChild('index'));
+		}
+	}
+
+	/**
+	 * @param Column $column
+	 * @param \SimpleXMLElement $xml
+	 */
+	private static function saveColumn($column, $xml) {
+		$xml->addChild('name', $column->getName());
+		switch($column->getType()) {
+			case 'SmallInt':
+			case 'Integer':
+			case 'BigInt':
+				$xml->addChild('type', 'integer');
+				$default = $column->getDefault();
+				if (is_null($default) && $column->getAutoincrement()) {
+					$default = '0';
+				}
+				$xml->addChild('default', $default);
+				$xml->addChild('notnull', self::toBool($column->getNotnull()));
+				if ($column->getAutoincrement()) {
+					$xml->addChild('autoincrement', '1');
+				}
+				if ($column->getUnsigned()) {
+					$xml->addChild('unsigned', 'true');
+				}
+				$length = '4';
+				if ($column->getType() == 'SmallInt') {
+					$length = '2';
+				}
+				elseif ($column->getType() == 'BigInt') {
+					$length = '8';
+				}
+				$xml->addChild('length', $length);
+				break;
+			case 'String':
+				$xml->addChild('type', 'text');
+				$default = trim($column->getDefault());
+				if ($default === '') {
+					$default = false;
+				}
+				$xml->addChild('default', $default);
+				$xml->addChild('notnull', self::toBool($column->getNotnull()));
+				$xml->addChild('length', $column->getLength());
+				break;
+			case 'Text':
+				$xml->addChild('type', 'clob');
+				$xml->addChild('notnull', self::toBool($column->getNotnull()));
+				break;
+			case 'Decimal':
+				$xml->addChild('type', 'decimal');
+				$xml->addChild('default', $column->getDefault());
+				$xml->addChild('notnull', self::toBool($column->getNotnull()));
+				$xml->addChild('length', '15');
+				break;
+			case 'Boolean':
+				$xml->addChild('type', 'integer');
+				$xml->addChild('default', $column->getDefault());
+				$xml->addChild('notnull', self::toBool($column->getNotnull()));
+				$xml->addChild('length', '1');
+				break;
+			case 'DateTime':
+				$xml->addChild('type', 'timestamp');
+				$xml->addChild('default', $column->getDefault());
+				$xml->addChild('notnull', self::toBool($column->getNotnull()));
+				break;
+
+		}
+	}
+
+	/**
+	 * @param Index $index
+	 * @param \SimpleXMLElement $xml
+	 */
+	private static function saveIndex($index, $xml) {
+		$xml->addChild('name', $index->getName());
+		if ($index->isPrimary()) {
+			$xml->addChild('primary', 'true');
+		}
+		elseif ($index->isUnique()) {
+			$xml->addChild('unique', 'true');
+		}
+		foreach($index->getColumns() as $column) {
+			$field = $xml->addChild('field');
+			$field->addChild('name', $column);
+			$field->addChild('sorting', 'ascending');
+			
+		}
+	}
+
+	private static function toBool($bool) {
+		return $bool ? 'true' : 'false';
+	}
+}
diff --git a/lib/private/DB/MigrationException.php b/lib/private/DB/MigrationException.php
new file mode 100644
index 00000000000..57e4c5b8334
--- /dev/null
+++ b/lib/private/DB/MigrationException.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+
+class MigrationException extends \Exception {
+	private $table;
+
+	public function __construct($table, $message) {
+		$this->table = $table;
+		parent::__construct($message);
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getTable() {
+		return $this->table;
+	}
+}
diff --git a/lib/private/DB/Migrator.php b/lib/private/DB/Migrator.php
new file mode 100644
index 00000000000..8b8a34d9865
--- /dev/null
+++ b/lib/private/DB/Migrator.php
@@ -0,0 +1,292 @@
+<?php
+/**
+ * @author martin-rueegg <martin.rueegg@metaworx.ch>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author tbelau666 <thomas.belau@gmx.de>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ * @author Victor Dubiniuk <dubiniuk@owncloud.com>
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use \Doctrine\DBAL\DBALException;
+use \Doctrine\DBAL\Schema\Index;
+use \Doctrine\DBAL\Schema\Table;
+use \Doctrine\DBAL\Schema\Schema;
+use \Doctrine\DBAL\Schema\SchemaConfig;
+use \Doctrine\DBAL\Schema\Comparator;
+use OCP\IConfig;
+use OCP\Security\ISecureRandom;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\EventDispatcher\GenericEvent;
+
+class Migrator {
+
+	/**
+	 * @var \Doctrine\DBAL\Connection $connection
+	 */
+	protected $connection;
+
+	/**
+	 * @var ISecureRandom
+	 */
+	private $random;
+
+	/** @var IConfig */
+	protected $config;
+
+	/** @var EventDispatcher  */
+	private $dispatcher;
+
+	/** @var bool */
+	private $noEmit = false;
+
+	/**
+	 * @param \Doctrine\DBAL\Connection|Connection $connection
+	 * @param ISecureRandom $random
+	 * @param IConfig $config
+	 * @param EventDispatcher $dispatcher
+	 */
+	public function __construct(\Doctrine\DBAL\Connection $connection,
+								ISecureRandom $random,
+								IConfig $config,
+								EventDispatcher $dispatcher = null) {
+		$this->connection = $connection;
+		$this->random = $random;
+		$this->config = $config;
+		$this->dispatcher = $dispatcher;
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $targetSchema
+	 */
+	public function migrate(Schema $targetSchema) {
+		$this->noEmit = true;
+		$this->applySchema($targetSchema);
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $targetSchema
+	 * @return string
+	 */
+	public function generateChangeScript(Schema $targetSchema) {
+		$schemaDiff = $this->getDiff($targetSchema, $this->connection);
+
+		$script = '';
+		$sqls = $schemaDiff->toSql($this->connection->getDatabasePlatform());
+		foreach ($sqls as $sql) {
+			$script .= $this->convertStatementToScript($sql);
+		}
+
+		return $script;
+	}
+
+	/**
+	 * @param Schema $targetSchema
+	 * @throws \OC\DB\MigrationException
+	 */
+	public function checkMigrate(Schema $targetSchema) {
+		$this->noEmit = true;
+		/**@var \Doctrine\DBAL\Schema\Table[] $tables */
+		$tables = $targetSchema->getTables();
+		$filterExpression = $this->getFilterExpression();
+		$this->connection->getConfiguration()->
+			setFilterSchemaAssetsExpression($filterExpression);
+		$existingTables = $this->connection->getSchemaManager()->listTableNames();
+
+		$step = 0;
+		foreach ($tables as $table) {
+			if (strpos($table->getName(), '.')) {
+				list(, $tableName) = explode('.', $table->getName());
+			} else {
+				$tableName = $table->getName();
+			}
+			$this->emitCheckStep($tableName, $step++, count($tables));
+			// don't need to check for new tables
+			if (array_search($tableName, $existingTables) !== false) {
+				$this->checkTableMigrate($table);
+			}
+		}
+	}
+
+	/**
+	 * Create a unique name for the temporary table
+	 *
+	 * @param string $name
+	 * @return string
+	 */
+	protected function generateTemporaryTableName($name) {
+		return $this->config->getSystemValue('dbtableprefix', 'oc_') . $name . '_' . $this->random->generate(13, ISecureRandom::CHAR_LOWER . ISecureRandom::CHAR_DIGITS);
+	}
+
+	/**
+	 * Check the migration of a table on a copy so we can detect errors before messing with the real table
+	 *
+	 * @param \Doctrine\DBAL\Schema\Table $table
+	 * @throws \OC\DB\MigrationException
+	 */
+	protected function checkTableMigrate(Table $table) {
+		$name = $table->getName();
+		$tmpName = $this->generateTemporaryTableName($name);
+
+		$this->copyTable($name, $tmpName);
+
+		//create the migration schema for the temporary table
+		$tmpTable = $this->renameTableSchema($table, $tmpName);
+		$schemaConfig = new SchemaConfig();
+		$schemaConfig->setName($this->connection->getDatabase());
+		$schema = new Schema(array($tmpTable), array(), $schemaConfig);
+
+		try {
+			$this->applySchema($schema);
+			$this->dropTable($tmpName);
+		} catch (DBALException $e) {
+			// pgsql needs to commit it's failed transaction before doing anything else
+			if ($this->connection->isTransactionActive()) {
+				$this->connection->commit();
+			}
+			$this->dropTable($tmpName);
+			throw new MigrationException($table->getName(), $e->getMessage());
+		}
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Table $table
+	 * @param string $newName
+	 * @return \Doctrine\DBAL\Schema\Table
+	 */
+	protected function renameTableSchema(Table $table, $newName) {
+		/**
+		 * @var \Doctrine\DBAL\Schema\Index[] $indexes
+		 */
+		$indexes = $table->getIndexes();
+		$newIndexes = array();
+		foreach ($indexes as $index) {
+			if ($index->isPrimary()) {
+				// do not rename primary key
+				$indexName = $index->getName();
+			} else {
+				// avoid conflicts in index names
+				$indexName = $this->config->getSystemValue('dbtableprefix', 'oc_') . $this->random->generate(13, ISecureRandom::CHAR_LOWER);
+			}
+			$newIndexes[] = new Index($indexName, $index->getColumns(), $index->isUnique(), $index->isPrimary());
+		}
+
+		// foreign keys are not supported so we just set it to an empty array
+		return new Table($newName, $table->getColumns(), $newIndexes, array(), 0, $table->getOptions());
+	}
+
+	protected function getDiff(Schema $targetSchema, \Doctrine\DBAL\Connection $connection) {
+		$filterExpression = $this->getFilterExpression();
+		$this->connection->getConfiguration()->
+		setFilterSchemaAssetsExpression($filterExpression);
+		$sourceSchema = $connection->getSchemaManager()->createSchema();
+
+		// remove tables we don't know about
+		/** @var $table \Doctrine\DBAL\Schema\Table */
+		foreach ($sourceSchema->getTables() as $table) {
+			if (!$targetSchema->hasTable($table->getName())) {
+				$sourceSchema->dropTable($table->getName());
+			}
+		}
+		// remove sequences we don't know about
+		foreach ($sourceSchema->getSequences() as $table) {
+			if (!$targetSchema->hasSequence($table->getName())) {
+				$sourceSchema->dropSequence($table->getName());
+			}
+		}
+
+		$comparator = new Comparator();
+		return $comparator->compare($sourceSchema, $targetSchema);
+	}
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $targetSchema
+	 * @param \Doctrine\DBAL\Connection $connection
+	 */
+	protected function applySchema(Schema $targetSchema, \Doctrine\DBAL\Connection $connection = null) {
+		if (is_null($connection)) {
+			$connection = $this->connection;
+		}
+
+		$schemaDiff = $this->getDiff($targetSchema, $connection);
+
+		$connection->beginTransaction();
+		$sqls = $schemaDiff->toSql($connection->getDatabasePlatform());
+		$step = 0;
+		foreach ($sqls as $sql) {
+			$this->emit($sql, $step++, count($sqls));
+			$connection->query($sql);
+		}
+		$connection->commit();
+	}
+
+	/**
+	 * @param string $sourceName
+	 * @param string $targetName
+	 */
+	protected function copyTable($sourceName, $targetName) {
+		$quotedSource = $this->connection->quoteIdentifier($sourceName);
+		$quotedTarget = $this->connection->quoteIdentifier($targetName);
+
+		$this->connection->exec('CREATE TABLE ' . $quotedTarget . ' (LIKE ' . $quotedSource . ')');
+		$this->connection->exec('INSERT INTO ' . $quotedTarget . ' SELECT * FROM ' . $quotedSource);
+	}
+
+	/**
+	 * @param string $name
+	 */
+	protected function dropTable($name) {
+		$this->connection->exec('DROP TABLE ' . $this->connection->quoteIdentifier($name));
+	}
+
+	/**
+	 * @param $statement
+	 * @return string
+	 */
+	protected function convertStatementToScript($statement) {
+		$script = $statement . ';';
+		$script .= PHP_EOL;
+		$script .= PHP_EOL;
+		return $script;
+	}
+
+	protected function getFilterExpression() {
+		return '/^' . preg_quote($this->config->getSystemValue('dbtableprefix', 'oc_')) . '/';
+	}
+
+	protected function emit($sql, $step, $max) {
+		if ($this->noEmit) {
+			return;
+		}
+		if(is_null($this->dispatcher)) {
+			return;
+		}
+		$this->dispatcher->dispatch('\OC\DB\Migrator::executeSql', new GenericEvent($sql, [$step+1, $max]));
+	}
+
+	private function emitCheckStep($tableName, $step, $max) {
+		if(is_null($this->dispatcher)) {
+			return;
+		}
+		$this->dispatcher->dispatch('\OC\DB\Migrator::checkTable', new GenericEvent($tableName, [$step+1, $max]));
+	}
+}
diff --git a/lib/private/DB/MySQLMigrator.php b/lib/private/DB/MySQLMigrator.php
new file mode 100644
index 00000000000..1b3f70a817d
--- /dev/null
+++ b/lib/private/DB/MySQLMigrator.php
@@ -0,0 +1,51 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Schema\Schema;
+
+class MySQLMigrator extends Migrator {
+	/**
+	 * @param Schema $targetSchema
+	 * @param \Doctrine\DBAL\Connection $connection
+	 * @return \Doctrine\DBAL\Schema\SchemaDiff
+	 */
+	protected function getDiff(Schema $targetSchema, \Doctrine\DBAL\Connection $connection) {
+		$platform = $connection->getDatabasePlatform();
+		$platform->registerDoctrineTypeMapping('enum', 'string');
+		$platform->registerDoctrineTypeMapping('bit', 'string');
+
+		$schemaDiff = parent::getDiff($targetSchema, $connection);
+
+		// identifiers need to be quoted for mysql
+		foreach ($schemaDiff->changedTables as $tableDiff) {
+			$tableDiff->name = $this->connection->quoteIdentifier($tableDiff->name);
+			foreach ($tableDiff->changedColumns as $column) {
+				$column->oldColumnName = $this->connection->quoteIdentifier($column->oldColumnName);
+			}
+		}
+
+		return $schemaDiff;
+	}
+}
diff --git a/lib/private/DB/NoCheckMigrator.php b/lib/private/DB/NoCheckMigrator.php
new file mode 100644
index 00000000000..23afae11816
--- /dev/null
+++ b/lib/private/DB/NoCheckMigrator.php
@@ -0,0 +1,38 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Schema\Schema;
+
+/**
+ * migrator for database platforms that don't support the upgrade check
+ *
+ * @package OC\DB
+ */
+class NoCheckMigrator extends Migrator {
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $targetSchema
+	 * @throws \OC\DB\MigrationException
+	 */
+	public function checkMigrate(Schema $targetSchema) {}
+}
diff --git a/lib/private/DB/OCSqlitePlatform.php b/lib/private/DB/OCSqlitePlatform.php
new file mode 100644
index 00000000000..fe68bc3cc91
--- /dev/null
+++ b/lib/private/DB/OCSqlitePlatform.php
@@ -0,0 +1,48 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+class OCSqlitePlatform extends \Doctrine\DBAL\Platforms\SqlitePlatform {
+	/**
+	 * {@inheritDoc}
+	 */
+	public function getColumnDeclarationSQL($name, array $field) {
+		$def = parent::getColumnDeclarationSQL($name, $field);
+		if (!empty($field['autoincrement'])) {
+			$def .= ' PRIMARY KEY AUTOINCREMENT';
+		}
+		return $def;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	protected function _getCreateTableSQL($name, array $columns, array $options = array()){
+		// if auto increment is set the column is already defined as primary key
+		foreach ($columns as $column) {
+			if (!empty($column['autoincrement'])) {
+				$options['primary'] = null;
+			}
+		}
+		return parent::_getCreateTableSQL($name, $columns, $options);
+	}
+}
diff --git a/lib/private/DB/OracleConnection.php b/lib/private/DB/OracleConnection.php
new file mode 100644
index 00000000000..a95f37a8e6c
--- /dev/null
+++ b/lib/private/DB/OracleConnection.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * @author Bart Visscher <bartv@thisnet.nl>
+ * @author Lukas Reschke <lukas@owncloud.com>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+class OracleConnection extends Connection {
+	/**
+	 * Quote the keys of the array
+	 */
+	private function quoteKeys(array $data) {
+		$return = array();
+		foreach($data as $key => $value) {
+			$return[$this->quoteIdentifier($key)] = $value;
+		}
+		return $return;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	public function insert($tableName, array $data, array $types = array()) {
+		$tableName = $this->quoteIdentifier($tableName);
+		$data = $this->quoteKeys($data);
+		return parent::insert($tableName, $data, $types);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	public function update($tableName, array $data, array $identifier, array $types = array()) {
+		$tableName = $this->quoteIdentifier($tableName);
+		$data = $this->quoteKeys($data);
+		$identifier = $this->quoteKeys($identifier);
+		return parent::update($tableName, $data, $identifier, $types);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	public function delete($tableExpression, array $identifier, array $types = array()) {
+		$tableName = $this->quoteIdentifier($tableExpression);
+		$identifier = $this->quoteKeys($identifier);
+		return parent::delete($tableName, $identifier);
+	}
+
+	/**
+	 * Drop a table from the database if it exists
+	 *
+	 * @param string $table table name without the prefix
+	 */
+	public function dropTable($table) {
+		$table = $this->tablePrefix . trim($table);
+		$table = $this->quoteIdentifier($table);
+		$schema = $this->getSchemaManager();
+		if($schema->tablesExist(array($table))) {
+			$schema->dropTable($table);
+		}
+	}
+
+	/**
+	 * Check if a table exists
+	 *
+	 * @param string $table table name without the prefix
+	 * @return bool
+	 */
+	public function tableExists($table){
+		$table = $this->tablePrefix . trim($table);
+		$table = $this->quoteIdentifier($table);
+		$schema = $this->getSchemaManager();
+		return $schema->tablesExist(array($table));
+	}
+}
diff --git a/lib/private/DB/OracleMigrator.php b/lib/private/DB/OracleMigrator.php
new file mode 100644
index 00000000000..ceb89cf64d4
--- /dev/null
+++ b/lib/private/DB/OracleMigrator.php
@@ -0,0 +1,74 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Schema\Schema;
+
+class OracleMigrator extends NoCheckMigrator {
+	/**
+	 * @param Schema $targetSchema
+	 * @param \Doctrine\DBAL\Connection $connection
+	 * @return \Doctrine\DBAL\Schema\SchemaDiff
+	 */
+	protected function getDiff(Schema $targetSchema, \Doctrine\DBAL\Connection $connection) {
+		$schemaDiff = parent::getDiff($targetSchema, $connection);
+
+		// oracle forces us to quote the identifiers
+		foreach ($schemaDiff->changedTables as $tableDiff) {
+			$tableDiff->name = $this->connection->quoteIdentifier($tableDiff->name);
+			foreach ($tableDiff->changedColumns as $column) {
+				$column->oldColumnName = $this->connection->quoteIdentifier($column->oldColumnName);
+			}
+		}
+
+		return $schemaDiff;
+	}
+
+	/**
+	 * @param string $name
+	 * @return string
+	 */
+	protected function generateTemporaryTableName($name) {
+		return 'oc_' . uniqid();
+	}
+
+	/**
+	 * @param $statement
+	 * @return string
+	 */
+	protected function convertStatementToScript($statement) {
+		if (substr($statement, -1) === ';') {
+			return $statement . PHP_EOL . '/' . PHP_EOL;
+		}
+		$script = $statement . ';';
+		$script .= PHP_EOL;
+		$script .= PHP_EOL;
+		return $script;
+	}
+
+	protected function getFilterExpression() {
+		return '/^"' . preg_quote($this->config->getSystemValue('dbtableprefix', 'oc_')) . '/';
+	}
+
+}
diff --git a/lib/private/DB/PgSqlTools.php b/lib/private/DB/PgSqlTools.php
new file mode 100644
index 00000000000..e9e507551e6
--- /dev/null
+++ b/lib/private/DB/PgSqlTools.php
@@ -0,0 +1,70 @@
+<?php
+/**
+ * @author Andreas Fischer <bantu@owncloud.com>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author tbelau666 <thomas.belau@gmx.de>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+use OCP\IConfig;
+
+/**
+* Various PostgreSQL specific helper functions.
+*/
+class PgSqlTools {
+
+	/** @var \OCP\IConfig */
+	private $config;
+
+	/**
+	 * @param \OCP\IConfig $config
+	 */
+	public function __construct(IConfig $config) {
+		$this->config = $config;
+	}
+
+	/**
+	* @brief Resynchronizes all sequences of a database after using INSERTs
+	*        without leaving out the auto-incremented column.
+	* @param \OC\DB\Connection $conn
+	* @return null
+	*/
+	public function resynchronizeDatabaseSequences(Connection $conn) {
+		$filterExpression = '/^' . preg_quote($this->config->getSystemValue('dbtableprefix', 'oc_')) . '/';
+		$databaseName = $conn->getDatabase();
+		$conn->getConfiguration()->setFilterSchemaAssetsExpression($filterExpression);
+
+		foreach ($conn->getSchemaManager()->listSequences() as $sequence) {
+			$sequenceName = $sequence->getName();
+			$sqlInfo = 'SELECT table_schema, table_name, column_name
+				FROM information_schema.columns
+				WHERE column_default = ? AND table_catalog = ?';
+			$sequenceInfo = $conn->fetchAssoc($sqlInfo, array(
+				"nextval('$sequenceName'::regclass)",
+				$databaseName
+			));
+			$tableName = $sequenceInfo['table_name'];
+			$columnName = $sequenceInfo['column_name'];
+			$sqlMaxId = "SELECT MAX($columnName) FROM $tableName";
+			$sqlSetval = "SELECT setval('$sequenceName', ($sqlMaxId))";
+			$conn->executeQuery($sqlSetval);
+		}
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/CompositeExpression.php b/lib/private/DB/QueryBuilder/CompositeExpression.php
new file mode 100644
index 00000000000..927dfe38378
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/CompositeExpression.php
@@ -0,0 +1,92 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder;
+
+use OCP\DB\QueryBuilder\ICompositeExpression;
+
+class CompositeExpression implements ICompositeExpression, \Countable {
+	/** @var \Doctrine\DBAL\Query\Expression\CompositeExpression */
+	protected $compositeExpression;
+
+	/**
+	 * Constructor.
+	 *
+	 * @param \Doctrine\DBAL\Query\Expression\CompositeExpression $compositeExpression
+	 */
+	public function __construct(\Doctrine\DBAL\Query\Expression\CompositeExpression $compositeExpression) {
+		$this->compositeExpression = $compositeExpression;
+	}
+
+	/**
+	 * Adds multiple parts to composite expression.
+	 *
+	 * @param array $parts
+	 *
+	 * @return \OCP\DB\QueryBuilder\ICompositeExpression
+	 */
+	public function addMultiple(array $parts = array()) {
+		$this->compositeExpression->addMultiple($parts);
+
+		return $this;
+	}
+
+	/**
+	 * Adds an expression to composite expression.
+	 *
+	 * @param mixed $part
+	 *
+	 * @return \OCP\DB\QueryBuilder\ICompositeExpression
+	 */
+	public function add($part) {
+		$this->compositeExpression->add($part);
+
+		return $this;
+	}
+
+	/**
+	 * Retrieves the amount of expressions on composite expression.
+	 *
+	 * @return integer
+	 */
+	public function count() {
+		return $this->compositeExpression->count();
+	}
+
+	/**
+	 * Returns the type of this composite expression (AND/OR).
+	 *
+	 * @return string
+	 */
+	public function getType() {
+		return $this->compositeExpression->getType();
+	}
+
+	/**
+	 * Retrieves the string representation of this composite expression.
+	 *
+	 * @return string
+	 */
+	public function __toString()
+	{
+		return (string) $this->compositeExpression;
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php
new file mode 100644
index 00000000000..ce98816c42d
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php
@@ -0,0 +1,370 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder\ExpressionBuilder;
+
+use Doctrine\DBAL\Query\Expression\ExpressionBuilder as DoctrineExpressionBuilder;
+use OC\DB\QueryBuilder\CompositeExpression;
+use OC\DB\QueryBuilder\Literal;
+use OC\DB\QueryBuilder\QueryFunction;
+use OC\DB\QueryBuilder\QuoteHelper;
+use OCP\DB\QueryBuilder\IExpressionBuilder;
+use OCP\IDBConnection;
+
+class ExpressionBuilder implements IExpressionBuilder {
+	/** @var \Doctrine\DBAL\Query\Expression\ExpressionBuilder */
+	protected $expressionBuilder;
+
+	/** @var QuoteHelper */
+	protected $helper;
+
+	/**
+	 * Initializes a new <tt>ExpressionBuilder</tt>.
+	 *
+	 * @param \OCP\IDBConnection $connection
+	 */
+	public function __construct(IDBConnection $connection) {
+		$this->helper = new QuoteHelper();
+		$this->expressionBuilder = new DoctrineExpressionBuilder($connection);
+	}
+
+	/**
+	 * Creates a conjunction of the given boolean expressions.
+	 *
+	 * Example:
+	 *
+	 *     [php]
+	 *     // (u.type = ?) AND (u.role = ?)
+	 *     $expr->andX('u.type = ?', 'u.role = ?'));
+	 *
+	 * @param mixed $x Optional clause. Defaults = null, but requires
+	 *                 at least one defined when converting to string.
+	 *
+	 * @return \OCP\DB\QueryBuilder\ICompositeExpression
+	 */
+	public function andX($x = null) {
+		$arguments = func_get_args();
+		$compositeExpression = call_user_func_array([$this->expressionBuilder, 'andX'], $arguments);
+		return new CompositeExpression($compositeExpression);
+	}
+
+	/**
+	 * Creates a disjunction of the given boolean expressions.
+	 *
+	 * Example:
+	 *
+	 *     [php]
+	 *     // (u.type = ?) OR (u.role = ?)
+	 *     $qb->where($qb->expr()->orX('u.type = ?', 'u.role = ?'));
+	 *
+	 * @param mixed $x Optional clause. Defaults = null, but requires
+	 *                 at least one defined when converting to string.
+	 *
+	 * @return \OCP\DB\QueryBuilder\ICompositeExpression
+	 */
+	public function orX($x = null) {
+		$arguments = func_get_args();
+		$compositeExpression = call_user_func_array([$this->expressionBuilder, 'orX'], $arguments);
+		return new CompositeExpression($compositeExpression);
+	}
+
+	/**
+	 * Creates a comparison expression.
+	 *
+	 * @param mixed $x The left expression.
+	 * @param string $operator One of the IExpressionBuilder::* constants.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function comparison($x, $operator, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->comparison($x, $operator, $y);
+	}
+
+	/**
+	 * Creates an equality comparison expression with the given arguments.
+	 *
+	 * First argument is considered the left expression and the second is the right expression.
+	 * When converted to string, it will generated a <left expr> = <right expr>. Example:
+	 *
+	 *     [php]
+	 *     // u.id = ?
+	 *     $expr->eq('u.id', '?');
+	 *
+	 * @param mixed $x The left expression.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function eq($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->eq($x, $y);
+	}
+
+	/**
+	 * Creates a non equality comparison expression with the given arguments.
+	 * First argument is considered the left expression and the second is the right expression.
+	 * When converted to string, it will generated a <left expr> <> <right expr>. Example:
+	 *
+	 *     [php]
+	 *     // u.id <> 1
+	 *     $q->where($q->expr()->neq('u.id', '1'));
+	 *
+	 * @param mixed $x The left expression.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function neq($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->neq($x, $y);
+	}
+
+	/**
+	 * Creates a lower-than comparison expression with the given arguments.
+	 * First argument is considered the left expression and the second is the right expression.
+	 * When converted to string, it will generated a <left expr> < <right expr>. Example:
+	 *
+	 *     [php]
+	 *     // u.id < ?
+	 *     $q->where($q->expr()->lt('u.id', '?'));
+	 *
+	 * @param mixed $x The left expression.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function lt($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->lt($x, $y);
+	}
+
+	/**
+	 * Creates a lower-than-equal comparison expression with the given arguments.
+	 * First argument is considered the left expression and the second is the right expression.
+	 * When converted to string, it will generated a <left expr> <= <right expr>. Example:
+	 *
+	 *     [php]
+	 *     // u.id <= ?
+	 *     $q->where($q->expr()->lte('u.id', '?'));
+	 *
+	 * @param mixed $x The left expression.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function lte($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->lte($x, $y);
+	}
+
+	/**
+	 * Creates a greater-than comparison expression with the given arguments.
+	 * First argument is considered the left expression and the second is the right expression.
+	 * When converted to string, it will generated a <left expr> > <right expr>. Example:
+	 *
+	 *     [php]
+	 *     // u.id > ?
+	 *     $q->where($q->expr()->gt('u.id', '?'));
+	 *
+	 * @param mixed $x The left expression.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function gt($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->gt($x, $y);
+	}
+
+	/**
+	 * Creates a greater-than-equal comparison expression with the given arguments.
+	 * First argument is considered the left expression and the second is the right expression.
+	 * When converted to string, it will generated a <left expr> >= <right expr>. Example:
+	 *
+	 *     [php]
+	 *     // u.id >= ?
+	 *     $q->where($q->expr()->gte('u.id', '?'));
+	 *
+	 * @param mixed $x The left expression.
+	 * @param mixed $y The right expression.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function gte($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->gte($x, $y);
+	}
+
+	/**
+	 * Creates an IS NULL expression with the given arguments.
+	 *
+	 * @param string $x The field in string format to be restricted by IS NULL.
+	 *
+	 * @return string
+	 */
+	public function isNull($x) {
+		$x = $this->helper->quoteColumnName($x);
+		return $this->expressionBuilder->isNull($x);
+	}
+
+	/**
+	 * Creates an IS NOT NULL expression with the given arguments.
+	 *
+	 * @param string $x The field in string format to be restricted by IS NOT NULL.
+	 *
+	 * @return string
+	 */
+	public function isNotNull($x) {
+		$x = $this->helper->quoteColumnName($x);
+		return $this->expressionBuilder->isNotNull($x);
+	}
+
+	/**
+	 * Creates a LIKE() comparison expression with the given arguments.
+	 *
+	 * @param string $x Field in string format to be inspected by LIKE() comparison.
+	 * @param mixed $y Argument to be used in LIKE() comparison.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function like($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->like($x, $y);
+	}
+
+	/**
+	 * Creates a ILIKE() comparison expression with the given arguments.
+	 *
+	 * @param string $x Field in string format to be inspected by ILIKE() comparison.
+	 * @param mixed $y Argument to be used in ILIKE() comparison.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 * @since 9.0.0
+	 */
+	public function iLike($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->comparison("LOWER($x)", 'LIKE', "LOWER($y)");
+	}
+
+	/**
+	 * Creates a NOT LIKE() comparison expression with the given arguments.
+	 *
+	 * @param string $x Field in string format to be inspected by NOT LIKE() comparison.
+	 * @param mixed $y Argument to be used in NOT LIKE() comparison.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function notLike($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->notLike($x, $y);
+	}
+
+	/**
+	 * Creates a IN () comparison expression with the given arguments.
+	 *
+	 * @param string $x The field in string format to be inspected by IN() comparison.
+	 * @param string|array $y The placeholder or the array of values to be used by IN() comparison.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function in($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnNames($y);
+		return $this->expressionBuilder->in($x, $y);
+	}
+
+	/**
+	 * Creates a NOT IN () comparison expression with the given arguments.
+	 *
+	 * @param string $x The field in string format to be inspected by NOT IN() comparison.
+	 * @param string|array $y The placeholder or the array of values to be used by NOT IN() comparison.
+	 * @param mixed|null $type one of the IQueryBuilder::PARAM_* constants
+	 *                  required when comparing text fields for oci compatibility
+	 *
+	 * @return string
+	 */
+	public function notIn($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnNames($y);
+		return $this->expressionBuilder->notIn($x, $y);
+	}
+
+	/**
+	 * Quotes a given input parameter.
+	 *
+	 * @param mixed $input The parameter to be quoted.
+	 * @param mixed|null $type One of the IQueryBuilder::PARAM_* constants
+	 *
+	 * @return Literal
+	 */
+	public function literal($input, $type = null) {
+		return new Literal($this->expressionBuilder->literal($input, $type));
+	}
+
+	/**
+	 * Returns a IQueryFunction that casts the column to the given type
+	 *
+	 * @param string $column
+	 * @param mixed $type One of IQueryBuilder::PARAM_*
+	 * @return string
+	 */
+	public function castColumn($column, $type) {
+		return new QueryFunction(
+			$this->helper->quoteColumnName($column)
+		);
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
new file mode 100644
index 00000000000..0d34787d26a
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder\ExpressionBuilder;
+
+
+use OC\DB\QueryBuilder\QueryFunction;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+
+class MySqlExpressionBuilder extends ExpressionBuilder {
+
+	/**
+	 * @inheritdoc
+	 */
+	public function iLike($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->comparison($x, ' COLLATE utf8_general_ci LIKE', $y);
+	}
+
+}
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php
new file mode 100644
index 00000000000..5d615ae52e8
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php
@@ -0,0 +1,163 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder\ExpressionBuilder;
+
+
+use OC\DB\QueryBuilder\QueryFunction;
+use OCP\DB\QueryBuilder\ILiteral;
+use OCP\DB\QueryBuilder\IParameter;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\DB\QueryBuilder\IQueryFunction;
+
+class OCIExpressionBuilder extends ExpressionBuilder {
+
+	/**
+	 * @param mixed $column
+	 * @param mixed|null $type
+	 * @return array|IQueryFunction|string
+	 */
+	protected function prepareColumn($column, $type) {
+		if ($type === IQueryBuilder::PARAM_STR && !is_array($column) && !($column instanceof IParameter) && !($column instanceof ILiteral)) {
+			$column = $this->castColumn($column, $type);
+		} else {
+			$column = $this->helper->quoteColumnNames($column);
+		}
+		return $column;
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function comparison($x, $operator, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->comparison($x, $operator, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function eq($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->eq($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function neq($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->neq($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function lt($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->lt($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function lte($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->lte($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function gt($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->gt($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function gte($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->gte($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function in($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->in($x, $y);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function notIn($x, $y, $type = null) {
+		$x = $this->prepareColumn($x, $type);
+		$y = $this->prepareColumn($y, $type);
+
+		return $this->expressionBuilder->notIn($x, $y);
+	}
+
+	/**
+	 * Returns a IQueryFunction that casts the column to the given type
+	 *
+	 * @param string $column
+	 * @param mixed $type One of IQueryBuilder::PARAM_*
+	 * @return IQueryFunction
+	 */
+	public function castColumn($column, $type) {
+		if ($type === IQueryBuilder::PARAM_STR) {
+			$column = $this->helper->quoteColumnName($column);
+			return new QueryFunction('to_char(' . $column . ')');
+		}
+
+		return parent::castColumn($column, $type);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function iLike($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return new QueryFunction('REGEXP_LIKE('.$x.', \'^\' || REPLACE('.$y.', \'%\', \'.*\') || \'$\', \'i\')');
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php
new file mode 100644
index 00000000000..a8f1af87a45
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder\ExpressionBuilder;
+
+
+use OC\DB\QueryBuilder\QueryFunction;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+
+class PgSqlExpressionBuilder extends ExpressionBuilder {
+
+	/**
+	 * Returns a IQueryFunction that casts the column to the given type
+	 *
+	 * @param string $column
+	 * @param mixed $type One of IQueryBuilder::PARAM_*
+	 * @return string
+	 */
+	public function castColumn($column, $type) {
+		if ($type === IQueryBuilder::PARAM_INT) {
+			$column = $this->helper->quoteColumnName($column);
+			return new QueryFunction('CAST(' . $column . ' AS INT)');
+		}
+
+		return parent::castColumn($column, $type);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function iLike($x, $y, $type = null) {
+		$x = $this->helper->quoteColumnName($x);
+		$y = $this->helper->quoteColumnName($y);
+		return $this->expressionBuilder->comparison($x, 'ILIKE', $y);
+	}
+
+}
diff --git a/lib/private/DB/QueryBuilder/Literal.php b/lib/private/DB/QueryBuilder/Literal.php
new file mode 100644
index 00000000000..0cc96ab48b4
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/Literal.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder;
+
+use OCP\DB\QueryBuilder\ILiteral;
+
+class Literal implements ILiteral{
+	/** @var mixed */
+	protected $literal;
+
+	public function __construct($literal) {
+		$this->literal = $literal;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function __toString() {
+		return (string) $this->literal;
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/Parameter.php b/lib/private/DB/QueryBuilder/Parameter.php
new file mode 100644
index 00000000000..1c233c83f1d
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/Parameter.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder;
+
+use OCP\DB\QueryBuilder\IParameter;
+
+class Parameter implements IParameter {
+	/** @var mixed */
+	protected $name;
+
+	public function __construct($name) {
+		$this->name = $name;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function __toString() {
+		return (string) $this->name;
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/QueryBuilder.php b/lib/private/DB/QueryBuilder/QueryBuilder.php
new file mode 100644
index 00000000000..bb463e43a75
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/QueryBuilder.php
@@ -0,0 +1,1124 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder;
+
+use Doctrine\DBAL\Platforms\MySqlPlatform;
+use Doctrine\DBAL\Platforms\PostgreSqlPlatform;
+use OC\DB\OracleConnection;
+use OC\DB\QueryBuilder\ExpressionBuilder\ExpressionBuilder;
+use OC\DB\QueryBuilder\ExpressionBuilder\MySqlExpressionBuilder;
+use OC\DB\QueryBuilder\ExpressionBuilder\OCIExpressionBuilder;
+use OC\DB\QueryBuilder\ExpressionBuilder\PgSqlExpressionBuilder;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\DB\QueryBuilder\IQueryFunction;
+use OCP\DB\QueryBuilder\IParameter;
+use OCP\IDBConnection;
+
+class QueryBuilder implements IQueryBuilder {
+
+	/** @var \OCP\IDBConnection */
+	private $connection;
+
+	/** @var \Doctrine\DBAL\Query\QueryBuilder */
+	private $queryBuilder;
+
+	/** @var QuoteHelper */
+	private $helper;
+
+	/** @var bool */
+	private $automaticTablePrefix = true;
+
+	/** @var string */
+	protected $lastInsertedTable;
+
+	/**
+	 * Initializes a new QueryBuilder.
+	 *
+	 * @param \OCP\IDBConnection $connection
+	 */
+	public function __construct(IDBConnection $connection) {
+		$this->connection = $connection;
+		$this->queryBuilder = new \Doctrine\DBAL\Query\QueryBuilder($this->connection);
+		$this->helper = new QuoteHelper();
+	}
+
+	/**
+	 * Enable/disable automatic prefixing of table names with the oc_ prefix
+	 *
+	 * @param bool $enabled If set to true table names will be prefixed with the
+	 * owncloud database prefix automatically.
+	 * @since 8.2.0
+	 */
+	public function automaticTablePrefix($enabled) {
+		$this->automaticTablePrefix = (bool) $enabled;
+	}
+
+	/**
+	 * Gets an ExpressionBuilder used for object-oriented construction of query expressions.
+	 * This producer method is intended for convenient inline usage. Example:
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u')
+	 *         ->from('users', 'u')
+	 *         ->where($qb->expr()->eq('u.id', 1));
+	 * </code>
+	 *
+	 * For more complex expression construction, consider storing the expression
+	 * builder object in a local variable.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IExpressionBuilder
+	 */
+	public function expr() {
+		if ($this->connection instanceof OracleConnection) {
+			return new OCIExpressionBuilder($this->connection);
+		} else if ($this->connection->getDatabasePlatform() instanceof PostgreSqlPlatform) {
+			return new PgSqlExpressionBuilder($this->connection);
+		} else if ($this->connection->getDatabasePlatform() instanceof MySqlPlatform) {
+			return new MySqlExpressionBuilder($this->connection);
+		} else {
+			return new ExpressionBuilder($this->connection);
+		}
+	}
+
+	/**
+	 * Gets the type of the currently built query.
+	 *
+	 * @return integer
+	 */
+	public function getType() {
+		return $this->queryBuilder->getType();
+	}
+
+	/**
+	 * Gets the associated DBAL Connection for this query builder.
+	 *
+	 * @return \OCP\IDBConnection
+	 */
+	public function getConnection() {
+		return $this->connection;
+	}
+
+	/**
+	 * Gets the state of this query builder instance.
+	 *
+	 * @return integer Either QueryBuilder::STATE_DIRTY or QueryBuilder::STATE_CLEAN.
+	 */
+	public function getState() {
+		return $this->queryBuilder->getState();
+	}
+
+	/**
+	 * Executes this query using the bound parameters and their types.
+	 *
+	 * Uses {@see Connection::executeQuery} for select statements and {@see Connection::executeUpdate}
+	 * for insert, update and delete statements.
+	 *
+	 * @return \Doctrine\DBAL\Driver\Statement|int
+	 */
+	public function execute() {
+		return $this->queryBuilder->execute();
+	}
+
+	/**
+	 * Gets the complete SQL string formed by the current specifications of this QueryBuilder.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u')
+	 *         ->from('User', 'u')
+	 *     echo $qb->getSQL(); // SELECT u FROM User u
+	 * </code>
+	 *
+	 * @return string The SQL query string.
+	 */
+	public function getSQL() {
+		return $this->queryBuilder->getSQL();
+	}
+
+	/**
+	 * Sets a query parameter for the query being constructed.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u')
+	 *         ->from('users', 'u')
+	 *         ->where('u.id = :user_id')
+	 *         ->setParameter(':user_id', 1);
+	 * </code>
+	 *
+	 * @param string|integer $key The parameter position or name.
+	 * @param mixed $value The parameter value.
+	 * @param string|null $type One of the IQueryBuilder::PARAM_* constants.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function setParameter($key, $value, $type = null) {
+		$this->queryBuilder->setParameter($key, $value, $type);
+
+		return $this;
+	}
+
+	/**
+	 * Sets a collection of query parameters for the query being constructed.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u')
+	 *         ->from('users', 'u')
+	 *         ->where('u.id = :user_id1 OR u.id = :user_id2')
+	 *         ->setParameters(array(
+	 *             ':user_id1' => 1,
+	 *             ':user_id2' => 2
+	 *         ));
+	 * </code>
+	 *
+	 * @param array $params The query parameters to set.
+	 * @param array $types The query parameters types to set.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function setParameters(array $params, array $types = array()) {
+		$this->queryBuilder->setParameters($params, $types);
+
+		return $this;
+	}
+
+	/**
+	 * Gets all defined query parameters for the query being constructed indexed by parameter index or name.
+	 *
+	 * @return array The currently defined query parameters indexed by parameter index or name.
+	 */
+	public function getParameters() {
+		return $this->queryBuilder->getParameters();
+	}
+
+	/**
+	 * Gets a (previously set) query parameter of the query being constructed.
+	 *
+	 * @param mixed $key The key (index or name) of the bound parameter.
+	 *
+	 * @return mixed The value of the bound parameter.
+	 */
+	public function getParameter($key) {
+		return $this->queryBuilder->getParameter($key);
+	}
+
+	/**
+	 * Gets all defined query parameter types for the query being constructed indexed by parameter index or name.
+	 *
+	 * @return array The currently defined query parameter types indexed by parameter index or name.
+	 */
+	public function getParameterTypes() {
+		return $this->queryBuilder->getParameterTypes();
+	}
+
+	/**
+	 * Gets a (previously set) query parameter type of the query being constructed.
+	 *
+	 * @param mixed $key The key (index or name) of the bound parameter type.
+	 *
+	 * @return mixed The value of the bound parameter type.
+	 */
+	public function getParameterType($key) {
+		return $this->queryBuilder->getParameterType($key);
+	}
+
+	/**
+	 * Sets the position of the first result to retrieve (the "offset").
+	 *
+	 * @param integer $firstResult The first result to return.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function setFirstResult($firstResult) {
+		$this->queryBuilder->setFirstResult($firstResult);
+
+		return $this;
+	}
+
+	/**
+	 * Gets the position of the first result the query object was set to retrieve (the "offset").
+	 * Returns NULL if {@link setFirstResult} was not applied to this QueryBuilder.
+	 *
+	 * @return integer The position of the first result.
+	 */
+	public function getFirstResult() {
+		return $this->queryBuilder->getFirstResult();
+	}
+
+	/**
+	 * Sets the maximum number of results to retrieve (the "limit").
+	 *
+	 * NOTE: Setting max results to "0" will cause mixed behaviour. While most
+	 * of the databases will just return an empty result set, Oracle will return
+	 * all entries.
+	 *
+	 * @param integer $maxResults The maximum number of results to retrieve.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function setMaxResults($maxResults) {
+		$this->queryBuilder->setMaxResults($maxResults);
+
+		return $this;
+	}
+
+	/**
+	 * Gets the maximum number of results the query object was set to retrieve (the "limit").
+	 * Returns NULL if {@link setMaxResults} was not applied to this query builder.
+	 *
+	 * @return integer The maximum number of results.
+	 */
+	public function getMaxResults() {
+		return $this->queryBuilder->getMaxResults();
+	}
+
+	/**
+	 * Specifies an item that is to be returned in the query result.
+	 * Replaces any previously specified selections, if any.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.id', 'p.id')
+	 *         ->from('users', 'u')
+	 *         ->leftJoin('u', 'phonenumbers', 'p', 'u.id = p.user_id');
+	 * </code>
+	 *
+	 * @param mixed $select The selection expressions.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function select($select = null) {
+		$selects = is_array($select) ? $select : func_get_args();
+
+		$this->queryBuilder->select(
+			$this->helper->quoteColumnNames($selects)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies an item that is to be returned with a different name in the query result.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->selectAlias('u.id', 'user_id')
+	 *         ->from('users', 'u')
+	 *         ->leftJoin('u', 'phonenumbers', 'p', 'u.id = p.user_id');
+	 * </code>
+	 *
+	 * @param mixed $select The selection expressions.
+	 * @param string $alias The column alias used in the constructed query.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function selectAlias($select, $alias) {
+
+		$this->queryBuilder->addSelect(
+			$this->helper->quoteColumnName($select) . ' AS ' . $this->helper->quoteColumnName($alias)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies an item that is to be returned uniquely in the query result.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->selectDistinct('type')
+	 *         ->from('users');
+	 * </code>
+	 *
+	 * @param mixed $select The selection expressions.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function selectDistinct($select) {
+
+		$this->queryBuilder->addSelect(
+			'DISTINCT ' . $this->helper->quoteColumnName($select)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds an item that is to be returned in the query result.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.id')
+	 *         ->addSelect('p.id')
+	 *         ->from('users', 'u')
+	 *         ->leftJoin('u', 'phonenumbers', 'u.id = p.user_id');
+	 * </code>
+	 *
+	 * @param mixed $select The selection expression.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function addSelect($select = null) {
+		$selects = is_array($select) ? $select : func_get_args();
+
+		$this->queryBuilder->addSelect(
+			$this->helper->quoteColumnNames($selects)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Turns the query being built into a bulk delete query that ranges over
+	 * a certain table.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->delete('users', 'u')
+	 *         ->where('u.id = :user_id');
+	 *         ->setParameter(':user_id', 1);
+	 * </code>
+	 *
+	 * @param string $delete The table whose rows are subject to the deletion.
+	 * @param string $alias The table alias used in the constructed query.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function delete($delete = null, $alias = null) {
+		$this->queryBuilder->delete(
+			$this->getTableName($delete),
+			$alias
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Turns the query being built into a bulk update query that ranges over
+	 * a certain table
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->update('users', 'u')
+	 *         ->set('u.password', md5('password'))
+	 *         ->where('u.id = ?');
+	 * </code>
+	 *
+	 * @param string $update The table whose rows are subject to the update.
+	 * @param string $alias The table alias used in the constructed query.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function update($update = null, $alias = null) {
+		$this->queryBuilder->update(
+			$this->getTableName($update),
+			$alias
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Turns the query being built into an insert query that inserts into
+	 * a certain table
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->insert('users')
+	 *         ->values(
+	 *             array(
+	 *                 'name' => '?',
+	 *                 'password' => '?'
+	 *             )
+	 *         );
+	 * </code>
+	 *
+	 * @param string $insert The table into which the rows should be inserted.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function insert($insert = null) {
+		$this->queryBuilder->insert(
+			$this->getTableName($insert)
+		);
+
+		$this->lastInsertedTable = $insert;
+
+		return $this;
+	}
+
+	/**
+	 * Creates and adds a query root corresponding to the table identified by the
+	 * given alias, forming a cartesian product with any existing query roots.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.id')
+	 *         ->from('users', 'u')
+	 * </code>
+	 *
+	 * @param string $from The table.
+	 * @param string|null $alias The alias of the table.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function from($from, $alias = null) {
+		$this->queryBuilder->from(
+			$this->getTableName($from),
+			$alias
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Creates and adds a join to the query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->join('u', 'phonenumbers', 'p', 'p.is_primary = 1');
+	 * </code>
+	 *
+	 * @param string $fromAlias The alias that points to a from clause.
+	 * @param string $join The table name to join.
+	 * @param string $alias The alias of the join table.
+	 * @param string $condition The condition for the join.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function join($fromAlias, $join, $alias, $condition = null) {
+		$this->queryBuilder->join(
+			$fromAlias,
+			$this->getTableName($join),
+			$alias,
+			$condition
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Creates and adds a join to the query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->innerJoin('u', 'phonenumbers', 'p', 'p.is_primary = 1');
+	 * </code>
+	 *
+	 * @param string $fromAlias The alias that points to a from clause.
+	 * @param string $join The table name to join.
+	 * @param string $alias The alias of the join table.
+	 * @param string $condition The condition for the join.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function innerJoin($fromAlias, $join, $alias, $condition = null) {
+		$this->queryBuilder->innerJoin(
+			$fromAlias,
+			$this->getTableName($join),
+			$alias,
+			$condition
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Creates and adds a left join to the query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->leftJoin('u', 'phonenumbers', 'p', 'p.is_primary = 1');
+	 * </code>
+	 *
+	 * @param string $fromAlias The alias that points to a from clause.
+	 * @param string $join The table name to join.
+	 * @param string $alias The alias of the join table.
+	 * @param string $condition The condition for the join.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function leftJoin($fromAlias, $join, $alias, $condition = null) {
+		$this->queryBuilder->leftJoin(
+			$fromAlias,
+			$this->getTableName($join),
+			$alias,
+			$condition
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Creates and adds a right join to the query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->rightJoin('u', 'phonenumbers', 'p', 'p.is_primary = 1');
+	 * </code>
+	 *
+	 * @param string $fromAlias The alias that points to a from clause.
+	 * @param string $join The table name to join.
+	 * @param string $alias The alias of the join table.
+	 * @param string $condition The condition for the join.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function rightJoin($fromAlias, $join, $alias, $condition = null) {
+		$this->queryBuilder->rightJoin(
+			$fromAlias,
+			$this->getTableName($join),
+			$alias,
+			$condition
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Sets a new value for a column in a bulk update query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->update('users', 'u')
+	 *         ->set('u.password', md5('password'))
+	 *         ->where('u.id = ?');
+	 * </code>
+	 *
+	 * @param string $key The column to set.
+	 * @param string $value The value, expression, placeholder, etc.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function set($key, $value) {
+		$this->queryBuilder->set(
+			$this->helper->quoteColumnName($key),
+			$this->helper->quoteColumnName($value)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies one or more restrictions to the query result.
+	 * Replaces any previously specified restrictions, if any.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->where('u.id = ?');
+	 *
+	 *     // You can optionally programatically build and/or expressions
+	 *     $qb = $conn->getQueryBuilder();
+	 *
+	 *     $or = $qb->expr()->orx();
+	 *     $or->add($qb->expr()->eq('u.id', 1));
+	 *     $or->add($qb->expr()->eq('u.id', 2));
+	 *
+	 *     $qb->update('users', 'u')
+	 *         ->set('u.password', md5('password'))
+	 *         ->where($or);
+	 * </code>
+	 *
+	 * @param mixed $predicates The restriction predicates.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function where($predicates) {
+		call_user_func_array(
+			[$this->queryBuilder, 'where'],
+			func_get_args()
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds one or more restrictions to the query results, forming a logical
+	 * conjunction with any previously specified restrictions.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u')
+	 *         ->from('users', 'u')
+	 *         ->where('u.username LIKE ?')
+	 *         ->andWhere('u.is_active = 1');
+	 * </code>
+	 *
+	 * @param mixed $where The query restrictions.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 *
+	 * @see where()
+	 */
+	public function andWhere($where) {
+		call_user_func_array(
+			[$this->queryBuilder, 'andWhere'],
+			func_get_args()
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds one or more restrictions to the query results, forming a logical
+	 * disjunction with any previously specified restrictions.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->where('u.id = 1')
+	 *         ->orWhere('u.id = 2');
+	 * </code>
+	 *
+	 * @param mixed $where The WHERE statement.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 *
+	 * @see where()
+	 */
+	public function orWhere($where) {
+		call_user_func_array(
+			[$this->queryBuilder, 'orWhere'],
+			func_get_args()
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies a grouping over the results of the query.
+	 * Replaces any previously specified groupings, if any.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->groupBy('u.id');
+	 * </code>
+	 *
+	 * @param mixed $groupBy The grouping expression.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function groupBy($groupBy) {
+		$groupBys = is_array($groupBy) ? $groupBy : func_get_args();
+
+		call_user_func_array(
+			[$this->queryBuilder, 'groupBy'],
+			$this->helper->quoteColumnNames($groupBys)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds a grouping expression to the query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->select('u.name')
+	 *         ->from('users', 'u')
+	 *         ->groupBy('u.lastLogin');
+	 *         ->addGroupBy('u.createdAt')
+	 * </code>
+	 *
+	 * @param mixed $groupBy The grouping expression.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function addGroupBy($groupBy) {
+		$groupBys = is_array($groupBy) ? $groupBy : func_get_args();
+
+		call_user_func_array(
+			[$this->queryBuilder, 'addGroupBy'],
+			$this->helper->quoteColumnNames($groupBys)
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Sets a value for a column in an insert query.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->insert('users')
+	 *         ->values(
+	 *             array(
+	 *                 'name' => '?'
+	 *             )
+	 *         )
+	 *         ->setValue('password', '?');
+	 * </code>
+	 *
+	 * @param string $column The column into which the value should be inserted.
+	 * @param string $value The value that should be inserted into the column.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function setValue($column, $value) {
+		$this->queryBuilder->setValue(
+			$this->helper->quoteColumnName($column),
+			$value
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies values for an insert query indexed by column names.
+	 * Replaces any previous values, if any.
+	 *
+	 * <code>
+	 *     $qb = $conn->getQueryBuilder()
+	 *         ->insert('users')
+	 *         ->values(
+	 *             array(
+	 *                 'name' => '?',
+	 *                 'password' => '?'
+	 *             )
+	 *         );
+	 * </code>
+	 *
+	 * @param array $values The values to specify for the insert query indexed by column names.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function values(array $values) {
+		$quotedValues = [];
+		foreach ($values as $key => $value) {
+			$quotedValues[$this->helper->quoteColumnName($key)] = $value;
+		}
+
+		$this->queryBuilder->values($quotedValues);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies a restriction over the groups of the query.
+	 * Replaces any previous having restrictions, if any.
+	 *
+	 * @param mixed $having The restriction over the groups.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function having($having) {
+		call_user_func_array(
+			[$this->queryBuilder, 'having'],
+			func_get_args()
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds a restriction over the groups of the query, forming a logical
+	 * conjunction with any existing having restrictions.
+	 *
+	 * @param mixed $having The restriction to append.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function andHaving($having) {
+		call_user_func_array(
+			[$this->queryBuilder, 'andHaving'],
+			func_get_args()
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds a restriction over the groups of the query, forming a logical
+	 * disjunction with any existing having restrictions.
+	 *
+	 * @param mixed $having The restriction to add.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function orHaving($having) {
+		call_user_func_array(
+			[$this->queryBuilder, 'orHaving'],
+			func_get_args()
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Specifies an ordering for the query results.
+	 * Replaces any previously specified orderings, if any.
+	 *
+	 * @param string $sort The ordering expression.
+	 * @param string $order The ordering direction.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function orderBy($sort, $order = null) {
+		$this->queryBuilder->orderBy(
+			$this->helper->quoteColumnName($sort),
+			$order
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Adds an ordering to the query results.
+	 *
+	 * @param string $sort The ordering expression.
+	 * @param string $order The ordering direction.
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function addOrderBy($sort, $order = null) {
+		$this->queryBuilder->addOrderBy(
+			$this->helper->quoteColumnName($sort),
+			$order
+		);
+
+		return $this;
+	}
+
+	/**
+	 * Gets a query part by its name.
+	 *
+	 * @param string $queryPartName
+	 *
+	 * @return mixed
+	 */
+	public function getQueryPart($queryPartName) {
+		return $this->queryBuilder->getQueryPart($queryPartName);
+	}
+
+	/**
+	 * Gets all query parts.
+	 *
+	 * @return array
+	 */
+	public function getQueryParts() {
+		return $this->queryBuilder->getQueryParts();
+	}
+
+	/**
+	 * Resets SQL parts.
+	 *
+	 * @param array|null $queryPartNames
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function resetQueryParts($queryPartNames = null) {
+		$this->queryBuilder->resetQueryParts($queryPartNames);
+
+		return $this;
+	}
+
+	/**
+	 * Resets a single SQL part.
+	 *
+	 * @param string $queryPartName
+	 *
+	 * @return \OCP\DB\QueryBuilder\IQueryBuilder This QueryBuilder instance.
+	 */
+	public function resetQueryPart($queryPartName) {
+		$this->queryBuilder->resetQueryPart($queryPartName);
+
+		return $this;
+	}
+
+	/**
+	 * Creates a new named parameter and bind the value $value to it.
+	 *
+	 * This method provides a shortcut for PDOStatement::bindValue
+	 * when using prepared statements.
+	 *
+	 * The parameter $value specifies the value that you want to bind. If
+	 * $placeholder is not provided bindValue() will automatically create a
+	 * placeholder for you. An automatic placeholder will be of the name
+	 * ':dcValue1', ':dcValue2' etc.
+	 *
+	 * For more information see {@link http://php.net/pdostatement-bindparam}
+	 *
+	 * Example:
+	 * <code>
+	 * $value = 2;
+	 * $q->eq( 'id', $q->bindValue( $value ) );
+	 * $stmt = $q->executeQuery(); // executed with 'id = 2'
+	 * </code>
+	 *
+	 * @license New BSD License
+	 * @link http://www.zetacomponents.org
+	 *
+	 * @param mixed $value
+	 * @param mixed $type
+	 * @param string $placeHolder The name to bind with. The string must start with a colon ':'.
+	 *
+	 * @return IParameter the placeholder name used.
+	 */
+	public function createNamedParameter($value, $type = IQueryBuilder::PARAM_STR, $placeHolder = null) {
+		return new Parameter($this->queryBuilder->createNamedParameter($value, $type, $placeHolder));
+	}
+
+	/**
+	 * Creates a new positional parameter and bind the given value to it.
+	 *
+	 * Attention: If you are using positional parameters with the query builder you have
+	 * to be very careful to bind all parameters in the order they appear in the SQL
+	 * statement , otherwise they get bound in the wrong order which can lead to serious
+	 * bugs in your code.
+	 *
+	 * Example:
+	 * <code>
+	 *  $qb = $conn->getQueryBuilder();
+	 *  $qb->select('u.*')
+	 *     ->from('users', 'u')
+	 *     ->where('u.username = ' . $qb->createPositionalParameter('Foo', IQueryBuilder::PARAM_STR))
+	 *     ->orWhere('u.username = ' . $qb->createPositionalParameter('Bar', IQueryBuilder::PARAM_STR))
+	 * </code>
+	 *
+	 * @param mixed $value
+	 * @param integer $type
+	 *
+	 * @return IParameter
+	 */
+	public function createPositionalParameter($value, $type = IQueryBuilder::PARAM_STR) {
+		return new Parameter($this->queryBuilder->createPositionalParameter($value, $type));
+	}
+
+	/**
+	 * Creates a new parameter
+	 *
+	 * Example:
+	 * <code>
+	 *  $qb = $conn->getQueryBuilder();
+	 *  $qb->select('u.*')
+	 *     ->from('users', 'u')
+	 *     ->where('u.username = ' . $qb->createParameter('name'))
+	 *     ->setParameter('name', 'Bar', IQueryBuilder::PARAM_STR))
+	 * </code>
+	 *
+	 * @param string $name
+	 *
+	 * @return IParameter
+	 */
+	public function createParameter($name) {
+		return new Parameter(':' . $name);
+	}
+
+	/**
+	 * Creates a new function
+	 *
+	 * Attention: Column names inside the call have to be quoted before hand
+	 *
+	 * Example:
+	 * <code>
+	 *  $qb = $conn->getQueryBuilder();
+	 *  $qb->select($qb->createFunction('COUNT(*)'))
+	 *     ->from('users', 'u')
+	 *  echo $qb->getSQL(); // SELECT COUNT(*) FROM `users` u
+	 * </code>
+	 * <code>
+	 *  $qb = $conn->getQueryBuilder();
+	 *  $qb->select($qb->createFunction('COUNT(`column`)'))
+	 *     ->from('users', 'u')
+	 *  echo $qb->getSQL(); // SELECT COUNT(`column`) FROM `users` u
+	 * </code>
+	 *
+	 * @param string $call
+	 *
+	 * @return IQueryFunction
+	 */
+	public function createFunction($call) {
+		return new QueryFunction($call);
+	}
+
+	/**
+	 * Used to get the id of the last inserted element
+	 * @return int
+	 * @throws \BadMethodCallException When being called before an insert query has been run.
+	 */
+	public function getLastInsertId() {
+		if ($this->getType() === \Doctrine\DBAL\Query\QueryBuilder::INSERT && $this->lastInsertedTable) {
+			// lastInsertId() needs the prefix but no quotes
+			$table = $this->prefixTableName($this->lastInsertedTable);
+			return (int) $this->connection->lastInsertId($table);
+		}
+
+		throw new \BadMethodCallException('Invalid call to getLastInsertId without using insert() before.');
+	}
+
+	/**
+	 * Returns the table name quoted and with database prefix as needed by the implementation
+	 *
+	 * @param string $table
+	 * @return string
+	 */
+	public function getTableName($table) {
+		$table = $this->prefixTableName($table);
+		return $this->helper->quoteColumnName($table);
+	}
+
+	/**
+	 * Returns the table name with database prefix as needed by the implementation
+	 *
+	 * @param string $table
+	 * @return string
+	 */
+	protected function prefixTableName($table) {
+		if ($this->automaticTablePrefix === false || strpos($table, '*PREFIX*') === 0) {
+			return $table;
+		}
+
+		return '*PREFIX*' . $table;
+	}
+
+	/**
+	 * Returns the column name quoted and with table alias prefix as needed by the implementation
+	 *
+	 * @param string $column
+	 * @param string $tableAlias
+	 * @return string
+	 */
+	public function getColumnName($column, $tableAlias = '') {
+		if ($tableAlias !== '') {
+			$tableAlias .= '.';
+		}
+
+		return $this->helper->quoteColumnName($tableAlias . $column);
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/QueryFunction.php b/lib/private/DB/QueryBuilder/QueryFunction.php
new file mode 100644
index 00000000000..ac6d73f3cbf
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/QueryFunction.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder;
+
+use OCP\DB\QueryBuilder\IQueryFunction;
+
+class QueryFunction implements IQueryFunction {
+	/** @var string */
+	protected $function;
+
+	public function __construct($function) {
+		$this->function = $function;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function __toString() {
+		return (string) $this->function;
+	}
+}
diff --git a/lib/private/DB/QueryBuilder/QuoteHelper.php b/lib/private/DB/QueryBuilder/QuoteHelper.php
new file mode 100644
index 00000000000..fda243a3786
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/QuoteHelper.php
@@ -0,0 +1,75 @@
+<?php
+/**
+ * @author Joas Schilling <nickvergessen@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB\QueryBuilder;
+
+use OCP\DB\QueryBuilder\ILiteral;
+use OCP\DB\QueryBuilder\IParameter;
+use OCP\DB\QueryBuilder\IQueryFunction;
+
+class QuoteHelper {
+	/**
+	 * @param array|string|ILiteral|IParameter|IQueryFunction $strings string, Literal or Parameter
+	 * @return array|string
+	 */
+	public function quoteColumnNames($strings) {
+		if (!is_array($strings)) {
+			return $this->quoteColumnName($strings);
+		}
+
+		$return = [];
+		foreach ($strings as $string) {
+			$return[] = $this->quoteColumnName($string);
+		}
+
+		return $return;
+	}
+
+	/**
+	 * @param string|ILiteral|IParameter|IQueryFunction $string string, Literal or Parameter
+	 * @return string
+	 */
+	public function quoteColumnName($string) {
+		if ($string instanceof IParameter || $string instanceof ILiteral || $string instanceof IQueryFunction) {
+			return (string) $string;
+		}
+
+		if ($string === null || $string === 'null' || $string === '*') {
+			return $string;
+		}
+
+		if (!is_string($string)) {
+			throw new \InvalidArgumentException('Only strings, Literals and Parameters are allowed');
+		}
+
+		if (substr_count($string, '.')) {
+			list($alias, $columnName) = explode('.', $string, 2);
+
+			if ($columnName === '*') {
+				return $string;
+			}
+
+			return $alias . '.`' . $columnName . '`';
+		}
+
+		return '`' . $string . '`';
+	}
+}
diff --git a/lib/private/DB/SQLiteMigrator.php b/lib/private/DB/SQLiteMigrator.php
new file mode 100644
index 00000000000..8ea32581011
--- /dev/null
+++ b/lib/private/DB/SQLiteMigrator.php
@@ -0,0 +1,81 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ * @author Victor Dubiniuk <dubiniuk@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\DBALException;
+use Doctrine\DBAL\Schema\Schema;
+
+class SQLiteMigrator extends Migrator {
+
+	/**
+	 * @param \Doctrine\DBAL\Schema\Schema $targetSchema
+	 * @throws \OC\DB\MigrationException
+	 *
+	 * For sqlite we simple make a copy of the entire database, and test the migration on that
+	 */
+	public function checkMigrate(\Doctrine\DBAL\Schema\Schema $targetSchema) {
+		$dbFile = $this->connection->getDatabase();
+		$tmpFile = $this->buildTempDatabase();
+		copy($dbFile, $tmpFile);
+
+		$connectionParams = array(
+			'path' => $tmpFile,
+			'driver' => 'pdo_sqlite',
+		);
+		$conn = \Doctrine\DBAL\DriverManager::getConnection($connectionParams);
+		try {
+			$this->applySchema($targetSchema, $conn);
+			$conn->close();
+			unlink($tmpFile);
+		} catch (DBALException $e) {
+			$conn->close();
+			unlink($tmpFile);
+			throw new MigrationException('', $e->getMessage());
+		}
+	}
+
+	/**
+	 * @return string
+	 */
+	private function buildTempDatabase() {
+		$dataDir = $this->config->getSystemValue("datadirectory", \OC::$SERVERROOT . '/data');
+		$tmpFile = uniqid("oc_");
+		return "$dataDir/$tmpFile.db";
+	}
+
+	/**
+	 * @param Schema $targetSchema
+	 * @param \Doctrine\DBAL\Connection $connection
+	 * @return \Doctrine\DBAL\Schema\SchemaDiff
+	 */
+	protected function getDiff(Schema $targetSchema, \Doctrine\DBAL\Connection $connection) {
+		$platform = $connection->getDatabasePlatform();
+		$platform->registerDoctrineTypeMapping('tinyint unsigned', 'integer');
+		$platform->registerDoctrineTypeMapping('smallint unsigned', 'integer');
+		$platform->registerDoctrineTypeMapping('varchar ', 'string');
+
+		return parent::getDiff($targetSchema, $connection);
+	}
+}
diff --git a/lib/private/DB/SQLiteSessionInit.php b/lib/private/DB/SQLiteSessionInit.php
new file mode 100644
index 00000000000..0683c47d08e
--- /dev/null
+++ b/lib/private/DB/SQLiteSessionInit.php
@@ -0,0 +1,65 @@
+<?php
+/**
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use Doctrine\DBAL\Event\ConnectionEventArgs;
+use Doctrine\DBAL\Events;
+use Doctrine\Common\EventSubscriber;
+
+class SQLiteSessionInit implements EventSubscriber {
+	/**
+	 * @var bool
+	 */
+	private $caseSensitiveLike;
+
+	/**
+	 * @var string
+	 */
+	private $journalMode;
+
+	/**
+	 * Configure case sensitive like for each connection
+	 *
+	 * @param bool $caseSensitiveLike
+	 * @param string $journalMode
+	 */
+	public function __construct($caseSensitiveLike, $journalMode) {
+		$this->caseSensitiveLike = $caseSensitiveLike;
+		$this->journalMode = $journalMode;
+	}
+
+	/**
+	 * @param ConnectionEventArgs $args
+	 * @return void
+	 */
+	public function postConnect(ConnectionEventArgs $args) {
+		$sensitive = ($this->caseSensitiveLike) ? 'true' : 'false';
+		$args->getConnection()->executeUpdate('PRAGMA case_sensitive_like = ' . $sensitive);
+		$args->getConnection()->executeUpdate('PRAGMA journal_mode = ' . $this->journalMode);
+	}
+
+	public function getSubscribedEvents() {
+		return array(Events::postConnect);
+	}
+}