Laravel Eloquent ORM - 删除事件和所有子关系，删除事件

Question

我有三个模型彼此相关：

国家

class Country extends Model
{
    protected $fillable=['name','sort'];
    public $timestamps=false;

    public function region(){
        return $this->hasMany('App\Models\Region');
    }
}

区域

class Region extends Model
{

    protected $fillable=['country_id','name','sort'];
    public  $timestamps=false;

    public function country()
    {
        return $this->belongsTo('App\Models\Country');
    }

    public function city()
    {
        return $this->hasMany('App\Models\City');
    }
}

城市

class City extends Model
{
    protected $table='cities';
    protected $fillable=['region_id','name','sort'];
    public  $timestamps=false;

    public function region()
    {
        return $this->belongsTo('App\Models\Region');
    }
}

当我们自动删除国家/地区时，删除所有子项目关系，即删除此区域和城市

我这样做：

模型国家

    public  static function boot() {
        parent::boot();

        static::deleting(function($country) {
            //remove related rows region and city

            // need an alternative variation of this code
            $country->region()->city()->delete();//not working
            $country->region()->delete();

            return true;
        });
    }
}

或者

模型区域

public  static function boot() {
        parent::boot();
        // this event do not working, when delete a parent(country)
        static::deleting(function($region) {
            dd($region);
            //remove related rows city
            $region->city()->delete();
            return true;
        });
    }
}

带有级联删除数据库的

选项，请不要提供

更新

我找到了答案

使用闭包查询构建器，删除相关模型

模型国家

public  static function boot() {
        parent::boot();

        static::deleting(function($country) {
            //remove related rows region and city
            $country->region->each(function($region) {
                $region->city()->delete();
            });
            $country->region()->delete();//
            return true;
        });
    }

Laravel Eloquent ORM - Removing rows and all the inner relationships

Answer 1

快速回顾一下：

$model->related_model将返回相关模型 $model->related_model()将返回关系对象。

您可以$model->related_model->delete()或$model->related_model()->get()->delete()访问模型上的delete()方法。

处理删除相关（或子）模型的另一种方法是在编写迁移时使用外键约束，请检查https://laravel.com/docs/master/migrations#foreign-key-constraints

Answer 2

我认为你可以在父对象的删除函数中做到这一点：

public function destroy_parent($id)
{
    $parent = PARENT::find($id);
    foreach ($parent->childs as $child){
            $child->delete();
    }
    $parent->delete();
    return redirect(...);
}