Laravel 5.2:如何从一对一(hasOne)关系中检索数据


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

我有两个模型:1.课程。2.费用。

一门课程只收一笔费用。在提供输入时,这是完全可以的,但当我试图访问费用数据时,费用栏中没有显示任何内容。我该如何解决?

课程模式:

<?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>

您似乎写错了关系。。。就这么做吧。

请记住,Course Has The Fee意味着Course是必须的,所以关系应该从Course一侧开始向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');
    }
}

现在你可以通过这样做来建立关系

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'));
}