查询关系Laravel雄辩ORM [英] Querying Relations Laravel Eloquent ORM

问题描述

我有一个问题的理解很好的关系，让我们来点

I have an issue understanding pretty well the Relationships, let's go to the point

我有3个表，其适当的模型

I have 3 tables, with its proper models

receipt
 - id
 - date

items_sold
 - id
 - receipt_id
 - item_id

items
 - id
 - name

我遇到的问题是收据有很多项目通过items_sold，但我不能使用hasManyThrough，因为雄辩使用错误item_sold的id，即使我手动键入

The problem I have is that receipt "has many" items through items_sold, but I can't use "hasManyThrough" because eloquent use the wrong "id" of "items_sold", even if I put manually the keys

class Receipt extends Eloquent {

    public function items()
    {
        return $this->hasManyThrough('Items', 'ItemsSold', 'receipt_id', 'id');
    }

}

没有办法通过这种方式，但我可以找到一个有说服力的关系方法，可以帮助我解决这个问题。

There is no way to do it in through this way, but I can find an Relationship method with eloquent that can help me with this case

推荐答案

正如lukasgeiter所说，添加到您的模型的 belongsToMany（）关系将允许您访问相关数据。

As lukasgeiter stated, a belongsToMany() relationship added to your models would allow you to access the related data.

还有其他要注意的事项如果您将连接表的名称更改为 item_reciept ，则可以在模型中定义多对多关系，而无需专门指定连接表。当Laravel看到没有指定连接表名称的 belongsToMany 方法时，它会查找涉及Snake案例和小写名称的字母顺序的两个模型的名称。

Something else to note, if you change your join table's name to item_reciept you can define the many to many relationship in your models without having to specify the join table specifically. When Laravel sees a belongsToMany method without a join table name specified, it looks for the name of the two models involved in snake case and alphabetical order with lower case names.

您的模型方法将是：

class Receipt extends Eloquent{

    public function items(){
        return $this->belongsToMany('Item');
    }
}

class Item extends Eloquent{

    public function reciepts(){
        return $this->belongsToMany('Reciept');
    }
}

我可以理解，如果你不想重命名您的 items_sold 表，因为它的具体名称表示它只是一个连接表的使用。

I can understand if you wouldn't want to rename your items_sold table because it's specific name denotes it's usage past just a join table.

另外需要注意的是，将这些关系添加到模型中，它允许您执行渴望加载您的请求，这可能对您的情况有帮助。

Another thing to note about adding these relationships to the model is that it allows your to perform eager loading with your requests which could be helpful in your situations.

假设您想要一次性获取特定收据的所有项目。您可以使用以下请求来获取所有内容：

Let's say you wanted to get all items for a specific receipt by it's id all in one go. You could use the following request to get everything together:

$receiptAndItems = Receipt::with('items')->find($recieptId);

这将返回您的特定收据记录和密钥项目的详细信息与该给定收据的所有相关项目记录：

This would return both the details on your particular Receipt record AND a key items with all of the related Item records for that given receipt:

// Your `receipt` record
// this is the output when you add `->toArray()` at the end to make it a bit easier to read

array (size=7)
  'id' => int 2
  'name' => string 'Foo' (length=12)
  'created_at' => string '2014-11-22 16:30:02' (length=19)
  'updated_at' => string '2014-11-22 16:30:02' (length=19)
  'items' => 
    array (size=3)
      0 => 
        array (size=7)
          'id' => int 1
          'name' => string 'Bar' (length=13)
          'created_at' => string '2014-11-22 16:30:02' (length=19)
          'updated_at' => string '2014-11-22 16:30:02' (length=19)
          'pivot' => 
            array (size=2)
              ...
      1 => 
        array (size=7)
          'id' => int 2
          'name' => string 'Baz' (length=20)
          'created_at' => string '2014-11-22 16:30:02' (length=19)
          'updated_at' => string '2014-11-22 16:30:02' (length=19)
          'pivot' => 
            array (size=2)
              ...
      2 => 
        array (size=7)
          'id' => int 3
          'name' => string 'FooBarBaz' (length=18)
          'created_at' => string '2014-11-22 16:30:02' (length=19)
          'updated_at' => string '2014-11-22 16:30:02' (length=19)
          'pivot' => 
            array (size=2)

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