将关系添加到透视表laravel中的附加值

// 在模型中定义多对多关系
class User extends Model
{
    public function roles()
    {
        return $this->belongsToMany(Role::class)->withPivot('additional_value');
    }
}

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

// 添加关系及附加值
$user = User::find(1);
$role = Role::find(1);
$user->roles()->attach($role, ['additional_value' => 'some value']);

// 获取附加值
$additionalValue = $user->roles()->where('role_id', $role->id)->first()->pivot->additional_value;