如何在 Laravel5 中将软删除的相关表记录设置为 Null

Question

我是 Laravel 的新手。

我有两个相互关联的表。

当其他相关表记录被软删除时，我想将相关表记录设置为null。

我知道当其他相关表记录时如何软删除，但是如何设置null而不是软删除？

产品型号（已编辑）

class Product extends Model
{
    use SoftDeletes;
    protected $dates = ['deleted_at'];

    public $table = "products";

    public function projects()
    {

        return $this->hasMany("App\Model\Project");

    }


    public static function boot(){

        parent::boot();

        static::deleted(function($product)
        {

            //set null
            $product->projects()->setNull();

        });

    }

}

项目模型（已编辑）

<?php

    class Project extends Model
    {
        use SoftDeletes;
        protected $dates = ['deleted_at'];

        public function product()
        {
            return $this->belongsTo("App\Model\Product");

        }

        public function setNull()
        {

            $this->product_id = NULL;
            $this->save();

        }

    }

表架构

        Schema::create('projects', function (Blueprint $table) {

            $table->increments('id');

            $table->string('project_name')->unique("project_name");
            $table->integer('project_value')->unsigned();


            $table->integer('product_id')->unsigned()->nullable(); 
            $table->foreign('product_id')->references('id')->on('products')->onDelete("set null");

            $table->timestamps();
            $table->softDeletes();

            $table->engine = 'InnoDB';

        });

注意

一个项目属于一个产品。看起来有点奇怪，但没关系。

错误信息

当我删除产品记录时，出现以下错误。

[2017-05-13 17:25:28] local.ERROR: BadMethodCallException: Call to undefined method Illuminate\Database\Query\Builder::setNull() in /vagrant/door/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php:2443
Stack trace:
#0 /vagrant/door/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(1239): Illuminate\Database\Query\Builder->__call('setNull', Array)
#1 [internal function]: Illuminate\Database\Eloquent\Builder->__call('setNull', Array)
#2 /vagrant/door/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/Relation.php(340): call_user_func_array(Array, Array)
#3 /vagrant/door/app/Model/Product.php(44): Illuminate\Database\Eloquent\Relations\Relation->__call('setNull', Array)
#4 /vagrant/door/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(348): App\Model\Product::App\Model\{closure}(Object(App\Model\Product))
#5 /vagrant/door/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(199): Illuminate\Events\Dispatcher->Illuminate\Events\{closure}('eloquent.delete...', Array)
#6 /vagrant/door/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(172): Illuminate\Events\Dispatcher->dispatch('eloquent.delete...', Array, false)
#7 /vagrant/door/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Concerns/HasEvents.php(148): Illuminate\Events\Dispatcher->fire('eloquent.delete...', Object(App\Model\Product))
#8 /vagrant/door/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php(748): Illuminate\Database\Eloquent\Model->fireModelEvent('deleted', false)
#9 /vagrant/door/app/Http/Controllers/ProductController.php(80): Illuminate\Database\Eloquent\Model->delete()
#10 [internal function]: App\Http\Controllers\ProductController->destroy(Object(App\Http\Requests\ProductRequest), '1')

Answer 1

查看dissociate() 方法，这将重置关系的外键和对象上的关系。

基本上你想要这样的东西：

static::deleted(function($product)
{
    // remove relation
    $product->projects()->each(function($project) {
        $project->product()->dissociate();
        $project->save();
    });
});

Answer 2

在您的项目模型中定义一个自定义方法，例如，

 public function setNull() 
{
 $this->field_names= NULL; 
$this->save(); 
}

然后在启动函数中你调用这个方法就像

$product->projects()->setNull(); 

P. S-对不起，我在手机上