diff options
Diffstat (limited to 'src/com/iciql/Db.java')
| -rw-r--r-- | src/com/iciql/Db.java | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/src/com/iciql/Db.java b/src/com/iciql/Db.java index cbc1ed4..bb087e4 100644 --- a/src/com/iciql/Db.java +++ b/src/com/iciql/Db.java @@ -74,6 +74,7 @@ public class Db { DIALECTS.put("H2", SQLDialectH2.class);
DIALECTS.put("MySQL", SQLDialectMySQL.class);
DIALECTS.put("HSQL Database Engine", SQLDialectHSQL.class);
+ DIALECTS.put("Apache Derby", SQLDialectDerby.class);
}
private Db(Connection conn) {
@@ -192,13 +193,30 @@ public class Db { * does exist. Not all databases support MERGE and the syntax varies with
* the database.
*
+ * If the database does not support a MERGE syntax the dialect can try to
+ * simulate a merge by implementing:
+ * <p>
+ * INSERT INTO foo... (SELECT ?,... FROM foo WHERE pk=? HAVING count(*)=0)
+ * <p>
+ * iciql will check the affected row count returned by the internal merge
+ * method and if the affected row count = 0, it will issue an update.
+ * <p>
+ * See the Derby dialect for an implementation of this technique.
+ * <p>
* If the dialect does not support merge an IciqlException will be thrown.
*
* @param t
*/
public <T> void merge(T t) {
Class<?> clazz = t.getClass();
- define(clazz).createTableIfRequired(this).merge(this, t);
+ TableDefinition<?> def = define(clazz).createTableIfRequired(this);
+ int rc = def.merge(this, t);
+ if (rc == 0) {
+ rc = def.update(this, t);
+ }
+ if (rc == 0) {
+ throw new IciqlException("merge failed");
+ }
}
public <T> int update(T t) {
@@ -220,7 +238,7 @@ public class Db { @SuppressWarnings("unchecked")
public <T> List<T> buildObjects(Class<? extends T> modelClass, ResultSet rs) {
List<T> result = new ArrayList<T>();
- TableDefinition<T> def = (TableDefinition<T>) define(modelClass).createTableIfRequired(this);
+ TableDefinition<T> def = (TableDefinition<T>) define(modelClass);
try {
while (rs.next()) {
T item = Utils.newObject(modelClass);
|