{ echo 'This is ' . __CLASS__ . ' ' . __FUNCTION__; } public function select() { echo 'This is ' . __CLASS__ . ' ' . __FUNCTION__; } } class MongoDB implements DB { public function create() { echo 'This is ' . __CLASS__ . ' ' . __FUNCTION__; } public function delete() { echo 'This is ' . __CLASS__ . ' ' . __FUNCTION__; } public function update() { echo 'This is ' . __CLASS__ . ' ' . __FUNCTION__; } public function select() { echo 'This is ' . __CLASS__ . ' ' . __FUNCTION__; } } $db1 = DBFactory::createDB('mongo'); $db2 = DBFactory::createDB('mysql'); $db1->update(); $db2->create();