Laravel 4多对多关系不工作，无法找到数据表 [英] Laravel 4 many to many relationship not working, pivot table not found

问题描述

我目前在与Laravel 4的n：n关系中遇到问题，我有一个错误wiht数据透视表，在一个表上，与两个组件在奇异的名字上。我创建一个数据透视表land_objs并填充它：

模型是：

 <？php 
 class Obj extends Eloquent 
 {
 protected $ guarded = array（）; 
 public static $ rules = array（）; 
 public $ timestamps = false; 
 public function land（）
 {
 return $ this-> belongsToMany（'Land'）; 
} 
 
<？php 
 
 class Land extends Eloquent 
 {
 protected $ guarded = array（）; 
 public static $ rules = array（）; 
 public $ timestamps = false; 
 
 public function objs（）
 {
 return $ this-> belongsToMany（'Obj'）; 
} 
} 
  

以下是按照标准填充数据透视表的方式。当然，还有land，objs和land_objs表：

 <？php 
 
 use Illuminate\ Database\Migrations\Migration; 
 
 class CreateLandsObjsTable extends Migration {
 
 / ** 
 *运行迁移。 
 * 
 * @return void 
 * / 
 public function up（）
 {
 Schema :: create（'lands_objs'，function ）{
 $ table-> integer（'land_id'）; 
 $ table-> integer（'obj_id'）; 
}）; 
} 
} 
  

有了这个结构，我应该能够感谢雄辩：

  $ land = Land :: find（1）; // checked loads land fine 
 $ objs = $ land-> objs; //  - >在这里我收到错误
  

但我收到错误：

  SQLSTATE [42S02]：未找到基表或视图：1146表'taylor.land_obj'不存在
（SQL：select`objs`。* ```````````````````````````````````````````````````````````` `obj_id` 
其中`land_obj`.`land_id` =？）（Bindings：array（0 => 1，））
  

尽管在land_obj上进行了查询，不应该Laravel创建表land_objs？我错过了什么吗？

非常感谢。

解决方案

枢轴表应该是链接的表名称的单数版本，按字母顺序，所以在您的情况下：

land_obj而不是land_objs

如果您不想使用默认的命名约定，您还可以在模型中的belongsToMany调用中将表名称指定为第二个参数：

  return $ this-> belongsToMany（'Obj'，'lands_objs'）; 
  

和

  return $ this-> belongsToMany（'Land'，'lands_objs'）; 
  

有关更多信息，请参阅这里的文档

I'm currently having problems with a n:n relationship with Laravel 4, I'm having an error wiht pivot table which is quering on a table with with both components on singular name. I create a pivot table lands_objs and populate it:

Models are:

<?php
    class Obj extends Eloquent
    {
        protected $guarded = array();
        public static $rules = array();
        public $timestamps = false;
        public function land()
        {
            return $this->belongsToMany('Land');
    }

<?php

    class Land extends Eloquent 
    {
        protected $guarded = array();
        public static $rules = array();
        public $timestamps = false;

        public function objs()
        {
            return $this->belongsToMany('Obj');
        }
     }

Here is how I populate the pivot table following the standards. Of course lands, objs and lands_objs tables exist:

<?php

use Illuminate\Database\Migrations\Migration;

class CreateLandsObjsTable extends Migration {

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('lands_objs', function($table) {
            $table->integer('land_id');
            $table->integer('obj_id');
        });
    }
}

With this structure I should be able to do thanks to Eloquent:

$land = Land::find(1);  //checked loads land fine
$objs = $land->objs; //--> HERE I TAKE THE ERROR

But I take the error:

SQLSTATE[42S02]: Base table or view not found: 1146 Table 'taylor.land_obj' doesn't exist
(SQL: select `objs`.*, `land_obj`.`land_id` as `pivot_land_id`, `land_obj`.`obj_id`
as `pivot_obj_id` from `objs` inner join `land_obj` on `objs`.`id` = `land_obj`.`obj_id`
where `land_obj`.`land_id` = ?) (Bindings: array ( 0 => 1, ))

Shouldn't Laravel create the table lands_objs in spite of quering on land_obj? Am I missing something?

Thanks a lot.

解决方案

The pivot table should be singular version of the table names it is linking, in alphabetical order so in your case:

land_obj rather than lands_objs

If you really don't want to use the default naming conventions you can also specify the table name as the 2nd param on the belongsToMany call in your models:

return $this->belongsToMany('Obj', 'lands_objs');

and

return $this->belongsToMany('Land', 'lands_objs');

For more information see docs here

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