From: James Ahlborn <jtahlborn@yahoo.com>
Date: Mon, 18 Apr 2011 01:52:57 +0000 (+0000)
Subject: add Index.getReferencedIndex for retrieving the referenced index of a foreign key... 
X-Git-Tag: jackcess-1.2.4~2
X-Git-Url: https://source.dussan.org/?a=commitdiff_plain;h=bb4ce1424cf8e4ef6c62e969e68884a6a0096024;p=jackcess.git

add Index.getReferencedIndex for retrieving the referenced index of a foreign key index

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@555 f203690c-595d-4dc9-a70b-905162fa7fd2
---

diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 5d97102..17d877c 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -22,6 +22,10 @@
         Access expects a row to be at least big enough to hold all fixed
         values, even if they are null.
       </action>
+      <action dev="jahlborn" type="update">
+        Add Index.getReferencedIndex for retrieving the referenced Index for a
+        foreign key index.
+      </action>
     </release>
     <release version="1.2.3" date="2011-03-05">
       <action dev="jahlborn" type="fix" issue="3181334">
diff --git a/src/java/com/healthmarketscience/jackcess/Database.java b/src/java/com/healthmarketscience/jackcess/Database.java
index 3691e22..3029881 100644
--- a/src/java/com/healthmarketscience/jackcess/Database.java
+++ b/src/java/com/healthmarketscience/jackcess/Database.java
@@ -1017,6 +1017,31 @@ public class Database
     return getTable(name, false, useBigIndex);
   }
 
+  /**
+   * @param tableDefPageNumber the page number of a table definition
+   * @return The table, or null if it doesn't exist
+   */
+  protected Table getTable(int tableDefPageNumber) throws IOException {
+
+    // first, check for existing table
+    Table table = _tableCache.get(tableDefPageNumber);
+    if(table != null) {
+      return table;
+    }
+    
+    // lookup table info from system catalog
+    Map<String,Object> objectRow = _tableFinder.getObjectRow(
+        tableDefPageNumber, SYSTEM_CATALOG_COLUMNS);
+    if(objectRow == null) {
+      return null;
+    }
+
+    String name = (String)objectRow.get(CAT_COL_NAME);
+    int flags = (Integer)objectRow.get(CAT_COL_FLAGS);
+
+    return readTable(name, tableDefPageNumber, flags, defaultUseBigIndex());
+  }
+
   /**
    * @param name Table name
    * @param includeSystemTables whether to consider returning a system table
diff --git a/src/java/com/healthmarketscience/jackcess/Index.java b/src/java/com/healthmarketscience/jackcess/Index.java
index c9c2bf4..532b4e1 100644
--- a/src/java/com/healthmarketscience/jackcess/Index.java
+++ b/src/java/com/healthmarketscience/jackcess/Index.java
@@ -164,6 +164,53 @@ public class Index implements Comparable<Index> {
     return _reference;
   }
 
+  /**
+   * @return the Index referenced by this Index's ForeignKeyReference (if it
+   *         has one), otherwise {@code null}.
+   */
+  public Index getReferencedIndex() throws IOException {
+
+    if(_reference == null) {
+      return null;
+    }
+
+    Table refTable = getTable().getDatabase().getTable(
+        _reference.getOtherTablePageNumber());
+
+    if(refTable == null) {
+      throw new IOException("Reference to missing table " + 
+                            _reference.getOtherTablePageNumber());
+    }
+
+    Index refIndex = null;
+    int idxNumber = _reference.getOtherIndexNumber();
+    for(Index idx : refTable.getIndexes()) {
+      if(idx.getIndexNumber() == idxNumber) {
+        refIndex = idx;
+        break;
+      }
+    }
+    
+    if(refIndex == null) {
+      throw new IOException("Reference to missing index " + idxNumber + 
+                            " on table " + refTable.getName());
+    }
+
+    // finally verify that we found the expected index (should reference this
+    // index)
+    ForeignKeyReference otherRef = refIndex.getReference();
+    if((otherRef == null) ||
+       (otherRef.getOtherTablePageNumber() != 
+        getTable().getTableDefPageNumber()) ||
+       (otherRef.getOtherIndexNumber() != _indexNumber)) {
+      throw new IOException("Found unexpected index " + refIndex.getName() +
+                            " on table " + refTable.getName() +
+                            " with reference " + otherRef);
+    }
+
+    return refIndex;
+  }
+
   /**
    * Whether or not {@code null} values are actually recorded in the index.
    */
diff --git a/test/src/java/com/healthmarketscience/jackcess/IndexTest.java b/test/src/java/com/healthmarketscience/jackcess/IndexTest.java
index 1e326c3..3ebfff6 100644
--- a/test/src/java/com/healthmarketscience/jackcess/IndexTest.java
+++ b/test/src/java/com/healthmarketscience/jackcess/IndexTest.java
@@ -466,6 +466,48 @@ public class IndexTest extends TestCase {
     }    
   }
   
+  public void testGetForeignKeyIndex() throws Exception
+  {
+    for (final TestDB testDB : TestDB.getSupportedForBasename(Basename.INDEX, true)) {
+      Database db = open(testDB);
+      Table t1 = db.getTable("Table1");
+      Table t2 = db.getTable("Table2");
+      Table t3 = db.getTable("Table3");
+
+      Index t2t1 = t1.getIndex(IndexTest.getRelationshipName(
+                                   db.getFormat(), "Table2Table1"));
+      Index t3t1 = t1.getIndex(IndexTest.getRelationshipName(
+                                   db.getFormat(), "Table3Table1"));
+
+
+      assertTrue(t2t1.isForeignKey());
+      assertNotNull(t2t1.getReference());
+      assertFalse(t2t1.getReference().isPrimaryTable());
+      doCheckForeignKeyIndex(t1, t2t1, t2);
+
+      assertTrue(t3t1.isForeignKey());
+      assertNotNull(t3t1.getReference());
+      assertFalse(t3t1.getReference().isPrimaryTable());
+      doCheckForeignKeyIndex(t1, t3t1, t3);
+      
+      Index t1pk = t1.getIndex(IndexBuilder.PRIMARY_KEY_NAME);
+      assertNotNull(t1pk);
+      assertNull(t1pk.getReference());
+      assertNull(t1pk.getReferencedIndex());
+    }    
+  }
+
+  private void doCheckForeignKeyIndex(Table ta, Index ia, Table tb)
+    throws Exception
+  {
+    Index ib = ia.getReferencedIndex();
+    assertNotNull(ib);
+    assertSame(tb, ib.getTable());
+
+    assertNotNull(ib.getReference());
+    assertSame(ia, ib.getReferencedIndex());
+  }
+
   private void checkIndexColumns(Table table, String... idxInfo)
     throws Exception
   {