Referential integrity constraints sometimes used the wrong index.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,10 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>The Polish translation was completed and corrected by Wojtek Jurczyk. Thanks a lot!
+<ul><li>Referential integrity constraints sometimes used the wrong index, 
+    such that updating a row in the referenced table incorrectly failed with
+    a constraint violation.
+</li><li>The Polish translation was completed and corrected by Wojtek Jurczyk. Thanks a lot!
 </li><li>Issue 545: Unnecessary duplicate code was removed. 
 </li><li>The profiler tool can now process files with full thread dumps.
 </li><li>MVStore: the file format was changed slightly.

h2/src/main/org/h2/command/ddl/AlterTableAddConstraint.java

@@ -327,16 +327,13 @@ public class AlterTableAddConstraint extends SchemaCommand {
             return false;
         }
         Column[] indexCols = existingIndex.getColumns();
-        if (indexCols.length < cols.length) {
+        if (indexCols.length != cols.length) {
             return false;
         }
         for (IndexColumn col : cols) {
-            // all columns of the list must be part of the index,
-            // but not all columns of the index need to be part of the list
-            // holes are not allowed (index=a,b,c & list=a,b is ok; but list=a,c
-            // is not)
+            // all columns of the list must be part of the index
             int idx = existingIndex.getColumnIndex(col.column);
-            if (idx < 0 || idx >= cols.length) {
+            if (idx < 0) {
                 return false;
             }
         }

h2/src/test/org/h2/test/db/TestCases.java

@@ -39,6 +39,7 @@ public class TestCases extends TestBase {
 
     @Override
     public void test() throws Exception {
+        testReferenceableIndexUsage();
         testClearSyntaxException();
         testEmptyStatements();
         testViewParameters();
@@ -102,6 +103,19 @@ public class TestCases extends TestBase {
         testBinaryCollation();
         deleteDb("cases");
     }
+    
+    private void testReferenceableIndexUsage() throws SQLException {
+        Connection conn = getConnection("cases");
+        Statement stat = conn.createStatement();
+        stat.execute("drop table if exists a, b");
+        stat.execute("create table a(id int, x int) as select 1, 100");
+        stat.execute("create index idx1 on a(id, x)");
+        stat.execute("create table b(id int primary key, a_id int) as select 1, 1");
+        stat.execute("alter table b add constraint x foreign key(a_id) references a(id)");
+        stat.execute("update a set x=200");
+        stat.execute("drop table if exists a, b");
+        conn.close();
+    }
 
     private void testClearSyntaxException() throws SQLException {
         Connection conn = getConnection("cases");