mysql - 违反完整性约束 : 1452 Cannot add or update a child row: a foreign key constraint fails

Question

我有用户和项目表。在项目表中，user_id 是外键。我创建了一个项目，当我尝试保存项目详细信息时显示此错误:

SQLSTATE[23000]:违反完整性约束:1452 无法添加或更新子行:外键约束失败(labtest。projects，CONSTRAINT projects_user_id_foreign FOREIGN KEY (user_id) REFERENCES users (id) ON UPDATE CASCADE) (SQL: 插入 Projects (name, description, date, updated_at, created_at) 值 ( e, e, 2017-12-31, 2017-09-19 15:21:06, 2017-09-19 15:21:06))

我该如何解决这个问题？

用户表迁移:

Schema::create('users', function (Blueprint $table) {
        $table->increments('id');
        $table->string('name');
        $table->string('email')->unique();
        $table->string('password');
        $table->rememberToken();
        $table->timestamps();
    });

项目表迁移

   Schema::create('projects', function (Blueprint $table) {
        $table->increments('id')->unique();
        $table->string('name');
        $table->text('description');
        $table->date('date');
        $table->timestamps('date');
    });



   Schema::table('projects',function(Blueprint $table)
    {
    $table->integer('user_id')->unsigned();
    $table->foreign('user_id')->references('id')->on('users')
    ->onUpdate('cascade');
    });

用户模型:

 public function project()
 {
     return $this->hasMany('App\Project');
  }

项目模型:

  public function user() {
      return $this->belongsTo('App\User','id','user_id');
   }

Controller :

  public function store(Request $request)
{

    $this->validate($request, [
        'name' => 'required',
        'description' => 'required',
        'date' => 'required',
    ]);


    Project::create($request->all());
    return redirect()->route('projects.index')
                    ->with('success','Project created successfully');
}

Answer 1

你有两个选择:

• 第一个:

  $data = $request->all();
  $data['user_id'] = Auth::user()->id;
  Project::create($data);
  //....
  

• 第二个:

  Auth::user()->project()->create($request->all());