Description: ------------ I am saving database structure to file and just than i am trying to restore database from that file. MDB2_Scheme is trying to update non-changing id field. MDB2 and MDB2_Driver_Mysql versions are last. Test script: --------------- 1. Saving db structure. // Db::$db is MDB2 object. $schema = &MDB2_Schema::factory( Db::$db ); $dbDef = $schema->getDefinitionFromDatabase(); $schema->dumpDatabase( $dbDef, array( 'output_mode'=>'file', 'output'=>'config/db.xml' ), MDB2_SCHEMA_DUMP_STRUCTURE ); 2. Updating database schema without changing db.xml. $schema = &MDB2_Schema::factory( Db::$db ); $dbCur = $schema->getDefinitionFromDatabase(); if (file_exists('config/db.xml')) { $dbNew = $schema->parseDatabaseDefinitionFile( 'config/db.xml' ); } echo $schema->updateDatabase( $dbNew, $dbCur )->getDebugInfo(); 3. Error is in MDB2_Driver_Mysql, line 790: if ($previous_default !== $default) { $change['default'] = true; } $previous_default is int and $previous is string. To fix it I replaced '!==' with '!='. Expected result: ---------------- No changes. Actual result: -------------- Error: _doQuery: [Error message: Could not execute statement] [Last query: ALTER TABLE subscribers CHANGE id id INT NOT NULL AUTO_INCREMENT PRIMARY KEY] [Native code: 1068] [Native message: Multiple primary key defined]