Laravel 5.2 : 如何检索一对一的数据 eloquent (hasOne) 关系

Question

我有两个模型： 1.课程。 2.费用.

一门课程只有一次费用。虽然提供输入是完全可以的，但是当我尝试访问费用数据时，它在费用栏中没有显示任何内容。我该如何解决？

课程模型：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Course extends Model
{
    protected $table='courses';
    protected $fillable = ['name'];


    public function fee(){
        return $this->belongsTo('App\Fee');
    }

}

收费模式：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Fee extends Model
{
        protected $table='fees';
    protected $fillable = ['fee','course_id'];
    public function course()
    {
        return $this->hasOne('App\Course');
    }
}

控制器：

public function listofCourse(){
        $course=\App\Course::all();
        return view('listofCourse',compact('course'));
    }

查看页面：

<html>
    <head> 
        <title> Course Details </title>

    <link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
    <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
    <script src="https://code.jquery.com/jquery-1.12.0.min.js"></script> 

    </head>
    <body>


<div class="container">
<h3> Student Details </h3>
      <table  class="table table-striped table-bordered"  id="example">
        <thead>
          <tr>
            <td>Serial No</td>
            <td>Course Name</td>
            <td>Course Fee</td>


        </tr>
        </thead>
        <tbody>
          <?php $i=1; ?>
        @foreach($course as $row)

          <tr>
            <td>{{$i}}</td>
            <td>{{$row->name }}</td>

            <td>    @if($row->course)
                  {{$row->course->fee}}
                   @endif</td>


             </tr>
          <?php $i++; ?>

        @endforeach
        </tbody>


      </table>

    </div>

    </body>
</html>

Answer 1

看来你把关系写错了……就这样吧

请记住，Course Has The Fee 意味着 Course 是必须的，所以关系应该从 Course 开始朝向 Fee。

您的课程模型

class Course extends Model
{
    protected $table='courses';
    protected $fillable = ['name'];


    public function fee(){
        return $this->hasOne('App\Fee','course_id', 'id');
    }

}

您的收费模式

class Fee extends Model
{
    protected $table='fees';
    protected $fillable = ['fee','course_id'];
    public function course()
    {
        return $this->belongsTO('App\Course', 'course_id', 'id');
    }
}

这样就可以得到关系了

public function listofCourse(){
        $course=\App\Course::with('fee')->get();
        // doing this for dumping purpose
        echo "<pre>"; 
        print_r($course->toArray()); // you will see the `fee` array
        echo "</pre>"; 
        die();
        return view('listofCourse',compact('course'));
}

Laravel 5.2 : 如何检索一对一的数据 eloquent (hasOne) 关系

Laravel 5.2 : How to retrieve data from one to one eloquent (hasOne) Relationship

php

one-to-one

laravel

eloquent

laravel-5.2