Laravel - 播种多对多关系

Question

我有一个

users

表和一个

roles

表，它们具有 多对多 关系。这两个表连接到一个名为

role_user

的联结表。

以下是我的 Laravel 项目中的模型：

用户

namespace App;

use Illuminate\Database\Eloquent\Model;

class User extends Model
{
    public function roles()
    {
        return $this->belongsToMany('App\Role');
    }
}

角色

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{
    public function users()
    {
        return $this->belongsToMany('App\User');
    }
}

下面是Laravel项目中的Factory文件：

$factory->define(App\User::class, function (Faker\Generator $faker) {
    return [
        'name' => $faker->name,
        'email' => $faker->unique()->safeEmail,
        'password' => $password ?: $password = bcrypt('secret'),
    ];
});

$factory->define(App\Role::class, function (Faker\Generator $faker) {
    return [
        'role' => $faker->realText($maxNbChars = 2),
        'description' => $faker->realText($maxNbChars = 20),
    ];
});

以下是 Laravel 项目中的种子文件：

public function run()
{
    factory(App\User::class, 50)->create()->each(function ($u) {
        $u->roles()->save(factory(App\Role::class)->make());
    });

    factory(App\Role::class, 20)->create()->each(function ($u) {
        $u->users()->save(factory(App\User::class)->make());
    });
}

这应该填充

users

表和

roles

表，但是我该如何填充

role_user

表呢？ （我没有连接表的模型文件。）

我对此很陌生，因此我们将不胜感激。谢谢。

Answer 1

您可以在多对多关系上使用

attach()

或

sync()

方法。

有多种方法可以解决这个问题。这是其中之一：

// Populate roles
factory(App\Role::class, 20)->create();

// Populate users
factory(App\User::class, 50)->create();

// Get all the roles attaching up to 3 random roles to each user
$roles = App\Role::all();

// Populate the pivot table
App\User::all()->each(function ($user) use ($roles) { 
    $user->roles()->attach(
        $roles->random(rand(1, 3))->pluck('id')->toArray()
    ); 
});

Answer 2

另一种方法是使用 saveMany() 函数

public function run()
{

   factory(App\User::class,3)->create();

   $roles = factory(App\Role::class,3)->create();

   App\User::All()->each(function ($user) use ($roles){
      $user->roles()->saveMany($roles);
   });
}

Answer 3

更简洁的方法可以是：在为 App\User 和 App\Roles 定义工厂后，您可以像这样调用 afterCreating 方法：

$factory->define(App\User::class, function ...);
$factory->define(App\Role::class, function ...);

$factory->afterCreating(App\User::class, function ($row, $faker) {
    $row->roles()->attach(rand(1,20));
});

然后在 Seeds 中，您首先创建角色，然后创建用户

public function run()
{
    factory(App\Role::class, 20)->create();
    factory(App\User::class, 50)->create();
}

现在您有 50 个用户，每个用户都附加一个角色。

Answer 4

仅对于播种机，您可以使用如下内容：

   for ($i = 0; $i < 50; $i++) {
        $user = factory(App\User::class)->create();

        $role = factory(App\Role::class)->create();

        DB::table('role_user')->insert([
            'user_id' => $user->id,
            'role_id' => $role->id
        ]);
    }

但通常你需要定义像有很多通过这样的关系https://laravel.com/docs/5.4/eloquent-relationships#has-many-through

然后您将可以使用：

$user->roles()->save($role);

Answer 5

最好使用这种结构：

App\Role::factory()->count(20)->create();

// Populate users
App\User::factory()->count(50)->create();

// Getting all roles and saving them to variable is not too good idea.
// Instead, get count of rows.
$rolesCount = App\Role::count();

// Populate the pivot table
App\User::all()->each(function ($user) use ($rolesCount) { 
    $user->roles()->attach(
        App\Role::all()->random(rand(1, $rolesCount))->pluck('id')->toArray()
    );
});

Answer 6

Laravel 9 及更高版本：

$roles = Role::factory()->count(10)->create();

$user->roles()->attach($roles);