确实不太好理解,主要是这些概念实在是又点绕,简单的理解呢,你可以把事件理解为钩子,举个例子,比如用户一登陆就自动发邮件和短信,或者数据库一执行sql就记录sql语句以便分析性能等,这是phalcon2的事件代码,你可以稍微理解下:

$eventsManager = new EventsManager();
// Create a database listener
$dbListener = new MyDbListener();
        
// Listen all the database events
$eventsManager->attach('db', $dbListener);
        
        $connection = new DbAdapter(
            array(
                "host" => "localhost",
                "username" => "root",
                "password" => "root",
                "dbname" => "phalcon2"
            )
        );
        // Assign the eventsManager to the db adapter instance
        $connection->setEventsManager($eventsManager);
        
        $connection->execute("SELECT * FROM items p WHERE p.types_id = 0");
        foreach ($dbListener->getProfiler()->getProfiles() as $profile) {
            echo "SQL Statement: ", $profile->getSQLStatement(), "<br />";
            echo "Start Time: ", $profile->getInitialTime(), "<br />";
            echo "Final Time: ", $profile->getFinalTime(), "<br />";
            echo "Total Elapsed Time: ", $profile->getTotalElapsedSeconds(), "<br />";
        }       

yii2的事件也差不多的,首先得on绑定,类似于phalcon2的attach附加到那个组件,目前yii2支持全局函数,对象以及类,回调绑定,然后在triggers触发就可以了,至于更深层次的理解,得多测试代码了!希望能帮到您!!

外键关联的,则会在外键赋值后会自动保存数据

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mark..