Laravel 多对多自引用表只能以一种方式工作
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Laravel Many to many self referencing table only works one way
提问by Al_
I have set up the relationship and the models as below:
我已经建立了关系和模型如下：
pivot table schema
数据透视表架构
Schema::create('friend_user', function(Blueprint $table) {
$table->increments('id');
$table->integer('user_id')->unsigned();
$table->integer('friend_id')->unsigned();
$table->timestamps();
});
pivot table seeder (this defines two 'friendships' to which user '1' belongs one where user 1 is specified in the user_id and the second where user 1 is listed in the friend id):
数据透视表播种机（这定义了用户“1”所属的两个“友谊”，一个是用户 1 在 user_id 中指定的，第二个是用户 1 在好友 ID 中列出的）：
$friend_user = array(
array(
'id' => 1,
'user_id' => 1,
'friend_id' => 3,
),
array(
'id' => 2,
'user_id' => 4,
'friend_id' => 1,
),
);
User model
用户模型
public function friends()
{
return $this->belongsToMany('User', 'friend_user', 'user_id', 'friend_id');
}
This is as suggested by Taylor Otwell here: https://github.com/laravel/framework/issues/441
这是由 Taylor Otwell 在这里建议的：https: //github.com/laravel/framework/issues/441
This all works but when I run the following command I get only one result:
这一切都有效，但是当我运行以下命令时，我只得到一个结果：
foreach(Auth::user()->friends as $i) {
var_dump($i->id);
}
This returns the value '3' but not 4 as expected. I understand why this is happening (as the user_id is not the friend_id) but how can I get this to return a collection of all friends belonging to a user (ie all friendships) regardless of which end of the connection (user_id or friend_id) the user is?
这将返回值 '3' 但不是预期的 4。我理解为什么会发生这种情况（因为 user_id 不是friend_id）但是我怎样才能让它返回属于一个用户的所有朋友（即所有朋友）的集合，而不管连接的哪一端（user_id 或friend_id）用户是？
回答by gettingThere
Instead of creating two records use a new function.
不是创建两个记录，而是使用新函数。
public function friends()
{
return $this->belongsToMany('User', 'friend_user', 'user_id', 'friend_id');
}
// Same table, self referencing, but change the key order
public function theFriends()
{
return $this->belongsToMany('User', 'friend_user', 'friend_id', 'user_id');
}
//You can then call opposite record(s) using:
foreach( Auth::user()->theFriends as $theFriends )
I used this approach in my project so I can have better separation for organizing the results.
我在我的项目中使用了这种方法，因此我可以更好地分离组织结果。
回答by Ando Hak
use this
用这个
public function friends()
{
return $this->belongsToMany('User', 'friend_user', 'user_id', 'friend_id')->orWhere('friend_id', $this->id);;
}
in this case you get one query and one record for each relation
在这种情况下，您会为每个关系获得一个查询和一个记录
