当我使用以下语法删除一行时:
$user->delete();
是否有一种方法来附加一个类型的回调,这样它就会自动这样做:
$this->photo()->delete();
最好是在模型类内部。
当我使用以下语法删除一行时:
$user->delete();
是否有一种方法来附加一个类型的回调,这样它就会自动这样做:
$this->photo()->delete();
最好是在模型类内部。
当前回答
我相信这是Eloquent事件(http://laravel.com/docs/eloquent#model-events)的一个完美用例。你可以使用"deleting"事件来进行清理:
class User extends Eloquent { public function photos() { return $this->has_many('Photo'); } // this is a recommended way to declare event handlers public static function boot() { parent::boot(); static::deleting(function($user) { // before delete() method call this $user->photos()->delete(); // do the rest of the cleanup... }); } } You should probably also put the whole thing inside a transaction, to ensure the referential integrity..
其他回答
是的,但是正如@supersan在上面的评论中所说,如果你在QueryBuilder上删除(),模型事件将不会被触发,因为我们没有加载模型本身,然后在该模型上调用delete()。
只有在模型实例上使用delete函数时,才会触发事件。
所以,有人说:
if user->hasMany(post)
and if post->hasMany(tags)
为了在删除用户时删除post标签,我们必须遍历$user->个帖子,并调用$post->delete()
Foreach ($user->posts as $post) {$post->delete();} ->这将在Post上触发删除事件
VS
$user->posts()->delete() ->这将不会在post上触发删除事件,因为我们实际上没有加载post模型(我们只运行SQL: delete *从user_id = $user->id的帖子,因此,post模型甚至没有加载)
使用限制()
Laravel 7之后,有了新的foreignId()和constrained()方法来定义数据库中的关系约束。可以在这些方法上使用OnDelete()方法自动删除相关记录。
古老的风格
$table->unsignedBigInterer('user_id');
$table->foreign('user_id')
->references('id')
->on('users')
->onDelete('cascade');
新风格
$table->foreignId('user_id')
->constrained()
->onDelete('cascade');
我相信这是Eloquent事件(http://laravel.com/docs/eloquent#model-events)的一个完美用例。你可以使用"deleting"事件来进行清理:
class User extends Eloquent { public function photos() { return $this->has_many('Photo'); } // this is a recommended way to declare event handlers public static function boot() { parent::boot(); static::deleting(function($user) { // before delete() method call this $user->photos()->delete(); // do the rest of the cleanup... }); } } You should probably also put the whole thing inside a transaction, to ensure the referential integrity..
我在《Laravel 8》中使用了这种方法:
public static function boot() {
parent::boot();
static::deleted(function($item){
$item->deleted_by = \Auth::id(); // to know who delete item, you can delete this row
$item->save(); // to know who delete item, you can delete this row
foreach ($item->photos as $photo){
$photo->delete();
}
});
}
public function photos()
{
return $this->hasMany('App\Models\Photos');
}
注意:在此语法中删除$user->photos()->delete();对我没用……
$table->foreignId('user_id')->constrained('user')->cascadeOnDelete();
or
$table->foreignId('user_id')->constrained()->cascadeOnDelete();