mysql - Eloquent - 多对多，用户主题按用户id删除所有主题

Question

考虑到 Eloquent 多对多关系:

迁移:

class Topics extends Migration
{
    public function up()
    {
        Schema::create('topics', function(Blueprint $table) {
            $table->increments('id');
            $table->string('name');
        });

        Schema::create('topic_user', function(Blueprint $table) {
            $table->integer('user_id')->unsigned();
            $table->foreign('user_id')->references('id')->on('users');
            $table->integer('topic_id')->unsigned();
            $table->foreign('topic_id')->references('id')->on('topics');
        });
    }
}

型号:

class User extends Model
{
    public function topics()
    {
        return $this->belongsToMany('App\Topic', 'topic_user');
    }
}

我想知道如何删除给定用户的所有主题，目前我的代码如下所示:

Auth::user()->topics()->delete();

但我遇到了异常:

ERROR: missing FROM-clause entry for table "topic_user" LINE 1: delete from "topics" where "topic_user"."user_id" = $1 ^ (SQL: delete from "topics" where "topic_user"."user_id" = 6)

我做错了什么？

Answer 1

这很简单:

Auth::user()->topics()->detach();