Laravel 多级关系以及与父相关的对应表

Question

抱歉，如果标题令人困惑，但让我试着澄清一下。 我有一个 students 表，后跟一个 processes 表，其中有一个 child 表 process tasks。然后我想，对于每个学生，每个流程都有对应的记录，同样，每个流程任务都有对应的记录。

例如：

Student ABC
Student DEF
Student GHI

Process 1: Enter Student Process
    - Process Task: Enter his name
    - Process Task: Phone the student
    - Process Task: Upload his photo

Process 2: Something else
    - Process Task: Tick this
    - Process Task: Tick that

这样我就可以为每个学生设置“待办事项列表”（流程及其相关任务），每个列表都有各自的状态。

（简化）表格

Schema::create('students', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('student_name',64);
        $table->string('student_surname',64);
        $table->timestamps();
    });

    Schema::create('processes', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('process')->nullable();
        $table->timestamps();
    });

    Schema::create('process_tasks', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->bigInteger('process_id')->unsigned()->index('process_id_index');
        $table->string('process_task')->nullable();
        $table->integer('sequence'); // task order
        $table->timestamps();
    });

    Schema::create('process_student', function (Blueprint $table) {
        $table->bigInteger('student_id')->unsigned();
        $table->bigInteger('process_id')->unsigned();
        $table->tinyInteger('status')->unsigned()->nullable(); // eg: awaiting feedback, due, etc
        $table->timestamps();
        $table->foreign('student_id', 'ps_student_id_foreign')->references('id')->on('students')->onDelete('cascade');
        $table->foreign('process_id', 'ps_process_id_foreign')->references('id')->on('processes')->onDelete('cascade');
    });

    Schema::create('process_task_student', function (Blueprint $table) {
        $table->bigInteger('student_id')->unsigned();
        $table->bigInteger('process_task_id')->unsigned();
        $table->boolean('complete')->default(0); // eg: awaiting feedback, due, etc
        $table->timestamps();
        $table->foreign('student_id', 'spt_student_id_foreign')->references('id')->on('students')->onDelete('cascade');
        $table->foreign('process_task_id', 'spt_process_task_id_foreign')->references('id')->on('process_tasks')->onDelete('cascade');
    });

模型/关系

流程

protected $fillable = [
    'process'
];

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

处理任务

protected $fillable = [
    'process_id',
    'process_task',
    'sequence'
];

学生

protected $fillable = [
    'id','student_name','student_surname'
];

public function processes() {
    return $this->belongsToMany('App\Process')->withTimestamps();
}

public function tasks() {
    return $this->processes()->belongsToMany('App\ProcessTask')->withTimestamps();
}

//编辑：添加了进一步的代码以进行澄清

控制器：

public function show($id)
{
    $student = Student::with(['processes','processes.tasks'])->findOrFail($id);
    return view('students.show', compact('student'));
}

查看：

@foreach ($student->processes as $student_process)
@foreach ($student_process->tasks->sortBy('sequence') as $student_process_task)
    <div class="kt-widget2__item kt-widget2__item--primary">
      <div class="kt-widget2__checkbox">
        <label class="kt-checkbox kt-checkbox--solid kt-checkbox--single">
        <input type="checkbox">
        <span></span>
        </label>
      </div>
      <div class="kt-widget2__info">
        <a href="#" class="kt-widget2__title">
            {{$student_process_task->process_task}}
        </a>
      </div>
    </div>
@endforeach
@endforeach

我觉得我的人际关系出了问题？我将如何获得该流程及其对特定学生的相关任务？

Answer 1

因此，学生和流程之间存在多对多关系，但流程和任务之间存在一对多关系。但是您也有一个用于流程任务关系的数据透视表。我很困惑。首先，确保添加反向关系，因为我没有看到任何关系。如果流程任务是多对多，则将 hasMany 更改为 belongsToMany。长话短说，请仔细检查您是否正确构建了所有关系。然后转到 StudentController.php 和

public function index()
{
  return Student::with("processes.tasks")->get();
}

在此页面https://laravel.com/docs/8.x/eloquent-relationships 中搜索“嵌套急切加载”以获取更多信息。