如何在Laravel中加入一对多关系 [英] How to group one to many relationships with join in Laravel

问题描述

我正在使用Laravel 5.3，并尝试使用联接从多个表中返回数据.

I'm using Laravel 5.3 and trying to return data from multiple tables using a join.

我正在使用3种模型/表格，分别是客户，业务和网站，这些模型/表格的相关性如下:

I'm using 3 models / tables, Customer, Business and Website which are related as follows:

在Customer.php中:

In Customer.php:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Customer extends Model
{
  public function businesses()
  {
    return $this->hasMany('App\Business');
  }
}

在Business.php中:

In Business.php:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Business extends Model
{
  public function customer() 
  {
    return $this->belongsTo('App\Customer');
  }

  public function websites()
  {
    return $this->hasMany('App\Website');
  }
}

在Website.php中:

And in Website.php:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Website extends Model
{  
  public function business() {
    return $this->belongsTo('App\Business');
  }
}

因此，客户可以具有许多 Business ，而这些企业可以具有许多网站.现在，我尝试使用join语句返回客户及其相关业务和网站信息的列表.我正在使用以下代码返回此信息:

So a Customer can have many Businesses which can have many Websites. Now I'm trying to use a join statement to return a list of the customers and their related business and website information. I'm using the following code to return this information:

$customers = \DB::table('customers')
                ->join('businesses', 'customers.id', '=', 'businesses.customer_id')
                ->join('websites', 'businesses.id', '=', 'websites.business_id')
                ->select('customers.x', 'businesses.y', 'websites.z')
                ->get();

我希望将数据以关联客户数组的形式返回，而将业务和网站数据嵌套在关联数组中，如下所示:

And I'd like the data to be return in an array of associative customer arrays with the business and websites data nested in the associative array like so:

[
  0 => {
    $customer1Data,
    $customer1BusinessData,
    $customer1WebsiteData
  }
  1 => {
   $customer2Data,
   $customer2BusinessData,
   $customer2WebsiteData
  }
  ...
]

如果客户经营一家拥有一个网站的企业，但假设 $ customer1 经营两家，则上述方法可以很好地工作，那么上述联接将以以下格式返回内容:

This works fine if a customer has one business which has one website but suppose $customer1 has two businesses, then the above join returns something in this format:

[
  0 => {
    $customer1Data,
    $customer1BusinessData1,
    $customer1WebsiteData
  }
  1 => {
   $customer1Data,
   $customer1BusinessData2,
   $customer1WebsiteData
  }
  ...
]

有没有一种方法可以修改join语句以这种格式返回该方案:

Is there a way I can modify the join statement to return that scenario in this format:

[
  0 => {
    $customer1Data,
    businesses => {
      $customer1BusinessData1,
      $customer1BusinessData2
    }
    ...
  }
] 

有没有一种方法可以通过join语句实现?还是我应该以不同的方式来处理这个问题?任何帮助将不胜感激，非常感谢.

Is there a way I can achieve this with join statements? Or should I be approaching this in a different way? Any help would be greatly appreciated, many thanks.

推荐答案

在我深入解释雄辩的模型关系之前，请阅读以下内容:

Before I dive into explaining eloquent model relations, read this: https://laravel.com/docs/5.4/eloquent. This will clear things up.

在模型关系中，您可以指定将这两个表链接在一起的数据库字段名称.这甚至适用于数据透视表.对于基本文档，请阅读以下内容: https://laravel.com/docs/5.4/eloquent-relationships#defining-relationships .

In a model relation you can specify what the database field names are that link those two tables together. This even works with pivot tables. For the basic documentation read this: https://laravel.com/docs/5.4/eloquent-relationships#defining-relationships.

例如在客户模型中:

public function businesses() 
{
    return $this->hasMany(Business::class, 'id', 'customer_id');
}

public function websites()
{
    //Argument order: final class, pivot class, pivot foreign key, foreign key final model, primary key start model (customer)
    return $this->hasManyThrough(Website::class, Business::class, 'customer_id', 'id', id);
}

如果最后一部分有点难以理解，请阅读文档:

If this last part was a bit hard to understand, read the documentation: https://laravel.com/docs/5.4/eloquent-relationships#has-many-through

对于商业模式:

public function website()
{
    return $this->hasMany(Website::class, 'id', 'business_id');
}

现在您可以使用雄辩的语言检索数据了.

And now you can retrieve data by using eloquent.

//This will retrieve all customers with all of their website information.
Customer::with('websites')->get();

//This will retrieve all customers with their business information.
Customer::with('businesses')->get();

//This will retrieve all customers with business and website information
//Retrieves: [ 
//    customer: [ 
//        customerDetails: [] 
//        businesses: [ b1, b2], 
//        websites: [w1, w2]
//    ]
//]
Customer::with('businesses', 'websites')->get();

//This will retrieve all customers with business information and the website information for each business
//Retrieves: [ 
//    customer: [ 
//        customerDetails: [] 
//        businesses: [ 
//            b1: [ websites: [w1] ],
//            b2: [ websites: [w2] ]
//        ], 
//    ]
//]
Customer::with('businesses.websites')->get();

我希望这会有所帮助！

这篇关于如何在Laravel中加入一对多关系的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！