TriggerAdapter: in "before" triggers, values can be changed using the ResultSet.updateX methods.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,14 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>The script created by SCRIPT DROP did not always work if multiple views
+<ul><li>TriggerAdapter: in "before" triggers, values can be changed using the ResultSet.updateX methods.
+</li><li>Creating a table with column data type NULL now works (even if not very useful).
+</li><li>ALTER TABLE ALTER COLUMN no longer copies the data for widening conversions
+    (for example if only the precision was increased) unless necessary.
+</li><li>Multi-threaded kernel: concurrently running an online backup
+    and updating the database resulted in a broken (transactionally incorrect) 
+    backup file in some cases.
+</li><li>The script created by SCRIPT DROP did not always work if multiple views
     existed that depend on each other.
 </li><li>MathUtils.getSecureRandom could log a warning to System.err in case
     the /dev/random is very slow, and the System.getProperties().toString()

h2/src/main/org/h2/tools/TriggerAdapter.java

@@ -17,6 +17,33 @@ import org.h2.api.Trigger;
  */
 public abstract class TriggerAdapter implements Trigger {
 
+    /**
+     * The schema name.
+     */
+    protected String schemaName;
+
+    /**
+     * The name of the trigger.
+     */
+    protected String triggerName;
+
+    /**
+     * The name of the table.
+     */
+    protected String tableName;
+
+    /**
+     * Whether the fire method is called before or after the operation is
+     * performed.
+     */
+    protected boolean before;
+
+    /**
+     * The trigger type: INSERT, UPDATE, DELETE, SELECT, or a combination (a bit
+     * field).
+     */
+    protected int type;
+
     private SimpleResultSet oldResultSet, newResultSet;
     private TriggerRowSource oldSource, newSource;
 
@@ -33,7 +60,8 @@ public abstract class TriggerAdapter implements Trigger {
      * @param tableName the name of the table
      * @param before whether the fire method is called before or after the
      *            operation is performed
-     * @param type the operation type: INSERT, UPDATE, or DELETE
+     * @param type the operation type: INSERT, UPDATE, DELETE, SELECT, or a
+     *            combination (this parameter is a bit field)
      */
     public void init(Connection conn, String schemaName,
             String triggerName, String tableName,
@@ -52,6 +80,11 @@ public abstract class TriggerAdapter implements Trigger {
             oldResultSet.addColumn(column, dataType, precision, scale);
             newResultSet.addColumn(column, dataType, precision, scale);
         }
+        this.schemaName = schemaName;
+        this.triggerName = triggerName;
+        this.tableName = tableName;
+        this.before = before;
+        this.type = type;
     }
 
     /**
@@ -112,6 +145,10 @@ public abstract class TriggerAdapter implements Trigger {
      * fire(Connection conn, Object[] oldRow, Object[] newRow) method.
      * ResultSet.next does not need to be called (and calling it has no effect;
      * it will always return true).
+     * <p>
+     * For "before" triggers, the new values of the new row may be changed
+     * using the ResultSet.updateX methods.
+     * </p>
      *
      * @param conn a connection to the database
      * @param oldRow the old row, or null if no old row is available (for

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

@@ -121,19 +121,25 @@ public class TestTriggersConstraints extends TestBase implements Trigger {
         stat.execute("drop table if exists test");
         stat.execute("create table test(id int)");
         stat.execute("create table message(name varchar)");
-        stat.execute("create trigger test_insert after insert, update, delete on test " +
+        stat.execute("create trigger test_insert before insert, update, delete on test " +
                 "for each row call \"" + TestTriggerAdapter.class.getName() + "\"");
         stat.execute("insert into test values(1)");
+        ResultSet rs;
+        rs = stat.executeQuery("select * from test");
+        rs.next();
+        assertEquals(10, rs.getInt(1));
         stat.execute("update test set id = 2");
+        rs = stat.executeQuery("select * from test");
+        rs.next();
+        assertEquals(20, rs.getInt(1));
         stat.execute("delete from test");
-        ResultSet rs;
         rs = stat.executeQuery("select * from message");
         assertTrue(rs.next());
         assertEquals("+1;", rs.getString(1));
         assertTrue(rs.next());
-        assertEquals("-1;+2;", rs.getString(1));
+        assertEquals("-10;+2;", rs.getString(1));
         assertTrue(rs.next());
-        assertEquals("-2;", rs.getString(1));
+        assertEquals("-20;", rs.getString(1));
         assertFalse(rs.next());
         stat.execute("drop table test, message");
         conn.close();
@@ -182,6 +188,30 @@ public class TestTriggersConstraints extends TestBase implements Trigger {
             if (newRow != null) {
                 buff.append("+").append(newRow.getString("id")).append(';');
             }
+            if (!"TEST_INSERT".equals(triggerName)) {
+                throw new RuntimeException("Wrong trigger name: " + triggerName);
+            }
+            if (!"TEST".equals(tableName)) {
+                throw new RuntimeException("Wrong table name: " + tableName);
+            }
+            if (!"PUBLIC".equals(schemaName)) {
+                throw new RuntimeException("Wrong schema name: " + schemaName);
+            }
+            if (type != (Trigger.INSERT | Trigger.UPDATE | Trigger.DELETE)) {
+                throw new RuntimeException("Wrong type: " + type);
+            }
+            if (newRow != null) {
+                if (oldRow == null) {
+                    if (newRow.getInt(1) != 1) {
+                        throw new RuntimeException("Expected: 1 got: " + newRow.getString(1));
+                    }
+                } else {
+                    if (newRow.getInt(1) != 2) {
+                        throw new RuntimeException("Expected: 2 got: " + newRow.getString(1));
+                    }
+                }
+                newRow.updateInt(1, newRow.getInt(1) * 10);
+            }
             conn.createStatement().execute("insert into message values('" + buff.toString() + "')");
         }