ALTER TABLE: removing an auto-increment or identity column didn't remove the sequence.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,8 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>Creating indexes is now a bit faster.
+<ul><li>ALTER TABLE: removing an auto-increment or identity column didn't remove the sequence.
+</li><li>Creating indexes is now a bit faster.
 </li><li>PG Server: new system property h2.pgClientEncoding to explicitly set the encoding
     for clients that don't send the encoding (the default encoding is UTF-8).
     Thanks a lot to Sergi Vladykin for the patch!

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

@@ -303,9 +303,9 @@ public class AlterTableAlterColumn extends SchemaCommand {
         }
         String tableName = table.getName();
         table.setModified();
-        for (Column col : columns) {
-            // if we don't do that, the sequence is dropped when the table is
-            // dropped
+        // remove the sequences from the columns (except dropped columns)
+        // otherwise the sequence is dropped if the table is dropped
+        for (Column col : newColumns) {
             Sequence seq = col.getSequence();
             if (seq != null) {
                 table.removeSequence(session, seq);

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

@@ -7,6 +7,7 @@
 package org.h2.test.db;
 
 import java.sql.Connection;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
 
@@ -35,10 +36,25 @@ public class TestAlter extends TestBase {
         conn = getConnection("alter");
         stat = conn.createStatement();
         testAlterTableAlterColumn();
+        testAlterTableDropIdentityColumn();
         conn.close();
         deleteDb("alter");
     }
 
+    private void testAlterTableDropIdentityColumn() throws SQLException {
+        stat.execute("create table test(id int auto_increment, name varchar)");
+        stat.execute("alter table test drop column id");
+        ResultSet rs = stat.executeQuery("select * from INFORMATION_SCHEMA.SEQUENCES");
+        assertFalse(rs.next());
+        stat.execute("drop table test");
+
+        stat.execute("create table test(id int auto_increment, name varchar)");
+        stat.execute("alter table test drop column name");
+        rs = stat.executeQuery("select * from INFORMATION_SCHEMA.SEQUENCES");
+        assertTrue(rs.next());
+        stat.execute("drop table test");
+    }
+
     private void testAlterTableAlterColumn() throws SQLException {
         stat.execute("create table t(x varchar) as select 'x'");
         try {