在 laravel 7 中使用工厂进行嵌套的一对多关系答案

【问题标题】：using factories for nested one to many relations in laravel 7在 laravel 7 中使用工厂进行嵌套的一对多关系
【发布时间】：2020-04-05 09:51:38
【问题描述】：

我在使用工厂时遇到了问题对于一对多关系中的三个嵌套级别这些是我的迁移：

    Schema::create('main_categories', function (Blueprint $table) {
        $table->id();
        $table->string('name', 100)->nullable(false);
    });

    Schema::create('categories', function (Blueprint $table) {
        $table->id();
        $table->string('name', 100)->nullable(false);

        $table->unsignedBigInteger('main_category_id');
        $table->foreign('main_category_id')
            ->references('id')
            ->on('main_categories')
            ->cascadeOnDelete();
    });

    Schema::create('sub_categories', function (Blueprint $table) {
        $table->id();
        $table->string('name', 100)->nullable(false);

        $table->unsignedBigInteger('category_id');
        $table->foreign('category_id')
            ->references('id')
            ->on('categories')
            ->cascadeOnDelete();
    });

这些是我的模型

class MainCategory extends Model
{
   ...

   public function categories()
   {
       return $this->hasMany(Category::class);
   }
}

class Category extends Model
{
    ...

    public function MainCategory()
    {
        return $this->belongsTo(MainCategory::class);
    }

    public function subCategories()
    {
        return $this->hasMany(SubCategory::class);
    }
}

class SubCategory extends Model
{
    ...

    public function category()
    {
        return $this->belongsTo(Category::class);
    }

    public function products()
    {
        return $this->hasMany(Product::class);
    }
}

这些是我的工厂：

$factory->define(MainCategory::class, function (Faker $faker) {
    return [
        'name'=>$faker->name
    ];
});
$factory->define(Category::class, function (Faker $faker) {
    return [
        'name' => $faker->name
    ];
});
$factory->define(SubCategory::class, function (Faker $faker) {
    return [
        'name' => $faker->name
    ];
});

我就这样使用这些工厂。我应该说，我想在创建 MainCategory 行时，立即创建 Category 如何与 MainCategory 有一对多关系，然后 SubCategory 应该创建如何与 Category 有一对多关系。我不知道我的错误在哪里：

factory(MainCategory::class, 5)->create()->each(function ($mainCategory) {
    $mainCategory->categories()->saveMany(factory(Category::class, 7)->make()->each(function ($category){
        $category->subCategories()->saveMany(factory(SubCategory::class, 7)->make());
    }));
});

【问题讨论】：

标签： factory laravel-7

【解决方案1】：

现在回答你有点晚了，但它可能对其他 Laravel 开发人员有用。我和你有同样的问题，经过一番思考，我建议你在你的代码中“休息一下”。像这样：

factory(MainCategory::class, 5)->create()->each(function ($mainCategory) {

    $mainCategory->categories()->saveMany(factory(Category::class, 7)->make();
    // Break
    $mainCategory->categories->each(function ($category){

        $category->subCategories()->saveMany(factory(SubCategory::class, 7)->make());
        // Break
        // $category->subcategories->each(function ($sub){
        //     ....
        // });

    }));

});

现在你可以做很多关系了。

【讨论】：