The sql contains mysql specific code. And for the mysql 5.0.xxx the sql statement has syntax error. in /Doctrine/DBAL/Platforms/MySqlPlatform.php: public function getListTableForeignKeysSQL($table, $database = null) { $sql = "SELECT DISTINCT k.`CONSTRAINT_NAME`, k.`COLUMN_NAME`, k.`REFERENCED_TABLE_NAME`, ". "k.`REFERENCED_COLUMN_NAME` /*!50116 , c.update_rule, c.delete_rule */ ". "FROM information_schema.key_column_usage k /*!50116 ". "INNER JOIN information_schema.referential_constraints c ON ". " c.constraint_name = k.constraint_name AND ". " c.table_name = '$table' */ WHERE k.table_name = '$table'"; if ($database) { $sql .= " AND k.table_schema = '$database' AND c.constraint_schema = '$database'"; } $sql .= " AND `REFERENCED_COLUMN_NAME` is not NULL"; return $sql; } For the mysql lower as 5.1.16 the SQL could be as the following: SELECT DISTINCT k.`CONSTRAINT_NAME`, k.`COLUMN_NAME`, k.`REFERENCED_TABLE_NAME`, k.`REFERENCED_COLUMN_NAME` FROM information_schema.key_column_usage k WHERE k.table_name = 'some_table' AND k.table_schema = 'some database' AND c.constraint_schema = 'some database' AND `REFERENCED_COLUMN_NAME` is not NULL In this statement there is no reference of c