Triggers: INSTEAD OF triggers are now supported.

h2/src/main/org/h2/schema/TriggerObject.java

@@ -35,6 +35,7 @@ public class TriggerObject extends SchemaObjectBase {
      */
     public static final int DEFAULT_QUEUE_SIZE = 1024;
 
+    private boolean insteadOf;
     private boolean before;
     private int typeMask;
     private boolean rowBased;
@@ -56,6 +57,10 @@ public class TriggerObject extends SchemaObjectBase {
         this.before = before;
     }
 
+    public void setInsteadOf(boolean insteadOf) {
+        this.insteadOf = insteadOf;
+    }
+
     private synchronized void load(Session session) throws SQLException {
         if (triggerCallback != null) {
             return;
@@ -148,14 +153,15 @@ public class TriggerObject extends SchemaObjectBase {
      * @param newRow the new row
      * @param beforeAction true if this method is called before the operation is
      *            applied
-     *  @param rollback when the operation occurred within a rollback
+     * @param rollback when the operation occurred within a rollback
+     * @return true if no further action is required (for 'instead of' triggers)
      */
-    public void fireRow(Session session, Row oldRow, Row newRow, boolean beforeAction, boolean rollback) throws SQLException {
+    public boolean fireRow(Session session, Row oldRow, Row newRow, boolean beforeAction, boolean rollback) throws SQLException {
         if (!rowBased || before != beforeAction) {
-            return;
+            return false;
         }
         if (rollback && !onRollback) {
-            return;
+            return false;
         }
         load(session);
         Object[] oldList;
@@ -177,7 +183,7 @@ public class TriggerObject extends SchemaObjectBase {
             }
         }
         if (!fire) {
-            return;
+            return false;
         }
         oldList = convertToObjectList(oldRow);
         newList = convertToObjectList(newRow);
@@ -217,6 +223,7 @@ public class TriggerObject extends SchemaObjectBase {
             session.setCommitOrRollbackDisabled(oldDisabled);
             session.setAutoCommit(old);
         }
+        return insteadOf;
     }
 
     /**
@@ -259,7 +266,9 @@ public class TriggerObject extends SchemaObjectBase {
     public String getCreateSQLForCopy(Table targetTable, String quotedName) {
         StringBuilder buff = new StringBuilder("CREATE FORCE TRIGGER ");
         buff.append(quotedName);
-        if (before) {
+        if (insteadOf) {
+            buff.append(" INSTEAD OF ");
+        } else if (before) {
             buff.append(" BEFORE ");
         } else {
             buff.append(" AFTER ");

h2/src/main/org/h2/table/Table.java

@@ -745,13 +745,15 @@ public abstract class Table extends SchemaObjectBase {
     /**
      * Fire all triggers that need to be called before a row is updated.
      *
-     *  @param session the session
-     *  @param oldRow the old data or null for an insert
-     *  @param newRow the new data or null for a delete
+     * @param session the session
+     * @param oldRow the old data or null for an insert
+     * @param newRow the new data or null for a delete
+     * @return true if no further action is required (for 'instead of' triggers)
      */
-    public void fireBeforeRow(Session session, Row oldRow, Row newRow) throws SQLException {
-        fireRow(session, oldRow, newRow, true, false);
+    public boolean fireBeforeRow(Session session, Row oldRow, Row newRow) throws SQLException {
+        boolean done = fireRow(session, oldRow, newRow, true, false);
         fireConstraints(session, oldRow, newRow, true);
+        return done;
     }
 
     private void fireConstraints(Session session, Row oldRow, Row newRow, boolean before) throws SQLException {
@@ -779,12 +781,16 @@ public abstract class Table extends SchemaObjectBase {
         }
     }
 
-    private void fireRow(Session session, Row oldRow, Row newRow, boolean beforeAction, boolean rollback) throws SQLException {
+    private boolean fireRow(Session session, Row oldRow, Row newRow, boolean beforeAction, boolean rollback) throws SQLException {
         if (triggers != null) {
             for (TriggerObject trigger : triggers) {
-                trigger.fireRow(session, oldRow, newRow, beforeAction, rollback);
+                boolean done = trigger.fireRow(session, oldRow, newRow, beforeAction, rollback);
+                if (done) {
+                    return true;
+                }
             }
         }
+        return false;
     }
 
     public boolean isGlobalTemporary() {

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

@@ -37,6 +37,7 @@ public class TestTriggersConstraints extends TestBase implements Trigger {
 
     public void test() throws SQLException {
         deleteDb("trigger");
+        testViewTrigger();
         testTriggerBeforeSelect();
         testTriggerAlterTable();
         testTriggers();
@@ -44,6 +45,49 @@ public class TestTriggersConstraints extends TestBase implements Trigger {
         deleteDb("trigger");
     }
 
+    private void testViewTrigger() throws SQLException {
+        Connection conn;
+        Statement stat;
+        conn = getConnection("trigger");
+        stat = conn.createStatement();
+        stat.execute("drop table if exists test");
+        stat.execute("create table test(id int)");
+        stat.execute("create view test_view as select * from test");
+        stat.execute("create trigger test_view_insert instead of insert on test_view for each row call \"" + TestView.class.getName() + "\"");
+        if (!config.memory) {
+            conn.close();
+            conn = getConnection("trigger");
+            stat = conn.createStatement();
+        }
+        stat.execute("insert into test_view values(1)");
+        ResultSet rs;
+        rs = stat.executeQuery("select * from test");
+        assertTrue(rs.next());
+        assertFalse(rs.next());
+        stat.execute("drop view test_view");
+        stat.execute("drop table test");
+        conn.close();
+    }
+
+    /**
+     * A test trigger implementation.
+     */
+    public static class TestView implements Trigger {
+
+        PreparedStatement prepInsert;
+
+        public void init(Connection conn, String schemaName, String triggerName, String tableName, boolean before,
+                int type) throws SQLException {
+            prepInsert = conn.prepareStatement("insert into test values(?)");
+        }
+
+        public void fire(Connection conn, Object[] oldRow, Object[] newRow) throws SQLException {
+            prepInsert.setInt(1, (Integer) newRow[0]);
+            prepInsert.execute();
+        }
+
+    }
+
     private void testTriggerBeforeSelect() throws SQLException {
         Connection conn;
         Statement stat;