Question

使用Laravel 5.5

假设我有一个User表和Conversation表，它们与ManyToMany关系有关。

用户

id用户

1 A

2 B

3 C

4 D

会话

id title

1 Conv1

2 Conv2

用户A，B和C与Conv1

相关联

用户B，C和D与Conv2相关联。

如果用户想要创建新的对话并选择A，B和C

如何验证与这些用户的对话以及仅存在这些用户？

public function postThread() {
    $thread = new Thread;
    $thread->title = request()->get('name');
    $thread->type = request()->get('type');
    /* How to verify if Thread exists with and only with all the users in request()->get('users') */
    Auth::user()->threads()->save($thread); //creates relation with new thread
    foreach (request()->get('users') as $user) {
        $user = User::find($user);
        $user->threads()->save($thread);//creates relation with every user    with new thread
    }
    $thread->save();
    return $thread;
    }

Answer 1

现在无法测试，但应该可以工作（仍然效率不高）

$users = $request->get('users');
$user = Auth::user();
$validThreads = $user->threads()->whereHas('users', function($query) use ($users){
   foreach( $users as $user_id) {
      $query->where('user_id',$user_id);
   }
});
// Valid threads is a collection of threads where all the users are present, now we need to check that no more users are present in that thread
$totalUsers = count($users)+1;
$thread = $validThreads->filter(function($thread) use ($totalUsers){
    return $thread->users()->count() == $totalUsers;
})->first();

if (is_null($thread)) {
    // The thread does not exists
}

Laravel验证是否存在多对多关系

1 个答案: