Laravel一对多的模特关系不起作用

问题描述：

I have a Booking model which can have many Service's.

I have defined the relationship in the Booking model like this:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use App\Service;

class Booking extends Model
{

    /**
     * Get the services for the booking.
     */
    public function services()
    {
        return $this->hasMany('App\Service');
    }
}

Then in my BookingController I try to get all the services for the current booking like this:

    public function create()
    {       
        $services = Booking::find(1)->services;
        return view('bookings.create');
    }

I keep getting the error:

Trying to get property of non-object

Not sure what I'm doing wrong here. The foreign key relation is all set up fine. I have a booking_id column in the services table which references id on the bookings table.

Any help would be appreciated.

我有Booking code>模型，可以有很多 Service code> 我已经在Booking模型中定义了这样的关系： p>

 ＆lt;？php 
 
namespace App;  
 
use Illuminate \ Database \ Eloquent \ Model; 
use App \ Service; 
 
class Booking extends Model 
 {
 
 / ** 
 *获取预订服务。
 * / \  n公共功能服务（）
 {
返回$ this-＆gt; hasMany（'App \ Service'）; 
} 
} 
  code>  pre> 
 
 然后 在我的 BookingController  code>中，我尝试获取当前预订的所有服务，如下所示： p> 
 
 
  public function create（）
 {
 $ services  = Booking :: find（1） - ＆gt; services; 
返回视图（'bookings.create'）; 
} 
  code>  pre> 
 
 我一直收到错误 ： p> 
 
 
 
 尝试获取非对象的属性 p> 
  blockquote> 
 
 
不确定我做错了什么 这里。 外键关系都设置得很好。 我在 services  code>表中有一个 booking_id  code>列，该列引用了 bookings  code>表中的 id  code>。 p> \  n 
 
我们将不胜感激。 p> 
  div>

答

In this particular case the issue is probably that Eloquent can't find a Booking with id == 1.

Booking::find(1); is going to query on the primary key for Booking for 1. If it is not found it will return null. Trying to use that null as an object is giving the "Trying to get property of non-object" error.

答

If your keys are not the ones generated by the laravel models you can try to specify them:

return $this->hasMany('App\Service', 'foreign_key', 'local_key');

答

public function create()
    {       
        $services = Booking::find(1)->services;
        return view('bookings.create');
    }

By seeing your above code: Ensure that you have record with id 1..if it is , check your primary and foreign key .

Laravel一对多的模特关系不起作用

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