Index: moodle_database.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/dml/moodle_database.php,v
retrieving revision 1.42
diff -u -r1.42 moodle_database.php
--- moodle_database.php	25 Jul 2008 23:31:08 -0000	1.42
+++ moodle_database.php	31 Jul 2008 08:03:24 -0000
@@ -456,6 +456,12 @@
     }
 
     /**
+     * Reset a sequence to the id field of a table.
+     * @return void
+     */
+    public abstract function reset_sequence($table);
+    
+    /**
      * Returns sql generator used for db manipulation.
      * Used mostly in upgrade.php scripts.
      * @return object database_manager instance
Index: mssql_adodb_moodle_database.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/dml/mssql_adodb_moodle_database.php,v
retrieving revision 1.15
diff -u -r1.15 mssql_adodb_moodle_database.php
--- mssql_adodb_moodle_database.php	28 Jun 2008 21:09:10 -0000	1.15
+++ mssql_adodb_moodle_database.php	31 Jul 2008 08:04:01 -0000
@@ -341,4 +341,21 @@
 
         return ($returnid ? $id : true);
     }
-}
+
+    /**
+     * Reset a sequence to the id field of a table.
+     * @return void
+     */
+    public function reset_sequence($table) {
+        // From http://msdn.microsoft.com/en-us/library/ms176057.aspx
+        $columns = $this->get_columns($table, false);
+        if(empty($columns['id'])) {
+            return;
+        }
+        $value = $this->get_field_sql('SELECT MAX(id) FROM {' . $table . '}');
+        if(!is_numeric($value)) {
+            $value = 1;
+        }
+        $this->change_database_structure("DBCC CHECKIDENT ('$this->prefix$table', RESEED, $value)");
+    }
+}
\ No newline at end of file
Index: mysqli_adodb_moodle_database.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/dml/mysqli_adodb_moodle_database.php,v
retrieving revision 1.9
diff -u -r1.9 mysqli_adodb_moodle_database.php
--- mysqli_adodb_moodle_database.php	16 Jun 2008 21:01:54 -0000	1.9
+++ mysqli_adodb_moodle_database.php	31 Jul 2008 08:04:23 -0000
@@ -274,4 +274,23 @@
     public function sql_regex($positivematch=true) {
         return $positivematch ? 'REGEXP' : 'NOT REGEXP';
     }
-}
+
+    /**
+     * Reset a sequence to the id field of a table.
+     * @return void
+     */
+    public function reset_sequence($table) {
+        // From http://dev.mysql.com/doc/refman/5.0/en/alter-table.html
+        $columns = $this->get_columns($table, false);
+        if(empty($columns['id'])) {
+            return;
+        }
+        $value = $this->get_field_sql('SELECT MAX(id) FROM {' . $table . '}');
+        if(is_numeric($value)) {
+            ++$value;
+        } else {
+            $value = 1;
+        }
+        $this->change_database_structure("ALTER TABLE $this->prefix$table AUTO_INCREMENT = $value");
+    }
+}
\ No newline at end of file
Index: oci8po_adodb_moodle_database.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/dml/oci8po_adodb_moodle_database.php,v
retrieving revision 1.16
diff -u -r1.16 oci8po_adodb_moodle_database.php
--- oci8po_adodb_moodle_database.php	26 Jun 2008 18:27:22 -0000	1.16
+++ oci8po_adodb_moodle_database.php	31 Jul 2008 08:04:56 -0000
@@ -597,4 +597,35 @@
     /// Fail safe to original value
         return $value;
     }
-}
+
+    /**
+     * Reset a sequence to the id field of a table.
+     * @return void
+     */
+    public function reset_sequence($table) {
+        // From http://www.acs.ilstu.edu/docs/oracle/server.101/b10759/statements_2011.htm
+        $columns = $this->get_columns($table, false);
+        if(empty($columns['id'])) {
+            return;
+        }
+        $value = $this->get_field_sql('SELECT MAX(id) FROM {'. $table . '}');
+        if(is_numeric($value)) {
+            ++$value;
+        } else {
+            $value = 1;
+        }
+        $dbman = $this->get_manager();
+        $xmldb_table = new xmldb_table($table);
+        $this->reads++;
+        $seqname = $dbman->find_sequence_name($xmldb_table);
+        if (!$seqname) {
+        /// Fallback, seqname not found, something is wrong. Inform and use the alternative getNameForObject() method
+            $generator = $dbman->generator;
+            $generator->setPrefix($this->getPrefix());
+            $seqname = $generator->getNameForObject($table, 'id', 'seq');
+        }
+
+        $this->change_database_structure("DROP SEQUENCE $seqname");
+        $this->change_database_structure("CREATE SEQUENCE $seqname START WITH $value INCREMENT BY 1 NOMAXVALUE");
+    }
+}
\ No newline at end of file
Index: postgres7_adodb_moodle_database.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/dml/postgres7_adodb_moodle_database.php,v
retrieving revision 1.15
diff -u -r1.15 postgres7_adodb_moodle_database.php
--- postgres7_adodb_moodle_database.php	22 Jun 2008 22:53:41 -0000	1.15
+++ postgres7_adodb_moodle_database.php	31 Jul 2008 08:06:10 -0000
@@ -461,4 +461,23 @@
     public function sql_regex($positivematch=true) {
         return $positivematch ? '~*' : '!~*';
     }
-}
+
+    /**
+     * Reset a sequence to the id field of a table.
+     * @return void
+     */
+    public function reset_sequence($table) {
+        // From http://www.postgresql.org/docs/7.4/static/sql-altersequence.html
+        $columns = $this->get_columns($table, false);
+        if(empty($columns['id'])) {
+            return;
+        }
+        $value = $this->get_field_sql('SELECT MAX(id) FROM {' . $table . '}');
+        if(is_numeric($value)) {
+            ++$value;
+        } else {
+            $value = 1;
+        }
+        $this->change_database_structure("ALTER SEQUENCE $this->prefix{$table}_id_seq RESTART WITH $value");
+    }
+}
\ No newline at end of file
Index: sqlite3_pdo_moodle_database.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/dml/sqlite3_pdo_moodle_database.php,v
retrieving revision 1.3
diff -u -r1.3 sqlite3_pdo_moodle_database.php
--- sqlite3_pdo_moodle_database.php	13 Jul 2008 10:12:21 -0000	1.3
+++ sqlite3_pdo_moodle_database.php	31 Jul 2008 08:06:42 -0000
@@ -323,4 +323,21 @@
         }
         return implode('||', $elements);
     }
+
+    /**
+     * Reset a sequence to the id field of a table.
+     * @return void
+     */
+    public function reset_sequence($table) {
+        // From http://sqlite.org/autoinc.html
+        $columns = $this->get_columns($table, false);
+        if(empty($columns['id'])) {
+            return;
+        }
+        $value = $this->get_field_sql('SELECT MAX(id) FROM {' . $table . '}');
+        if(!is_numeric($value)) {
+            $value = 0;
+        }
+        $this->change_database_structure("UPDATE sqlite_sequence SET seq=$value WHERE name='$this->prefix$table'");
+    }
 }
\ No newline at end of file