php - Laravel Eloquent，如何用公式定义表关系？

Question

关于 Laravel Eloquent ，

如何使用表中不存在但根据表中的值计算得出的内容来定义关系条件。

例如:

quarters                transactions
 _________ _________    _________ ___________
|   name  |  desc   |  |   id  |  date        |
 _________ _________    _________ ___________
|     1   | Jan-Mar |  |     1   | 2016-04-01 |
|     2   | Apr-Jun |  |     2   | 2016-05-01 |
|     3   | Jul-Sep |  |     3   | 2012-07-21 |
|     4   | Oct-Dec |  |     4   | 2014-01-31 |
 _________ _________    _________ ___________

用这个很好用

SELECT 
FROM transactions tx
INNER JOIN quarters q ON q.name = ((MONTH(tx.date)+2)/3)

Quarters.php

<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;
class Quarters extends Model{

}

交易.php

namespace App\Models;
use Illuminate\Database\Eloquent\Model;
class Transactions extends Model{

    public function quater(){
        return $this->belongsTo('App\Models\Quarters' , '????', 'name') ;
    }
}

我应该在模型中定义什么才能执行以下操作: 交易::where("some_field", "some_value")->with("quater")->get()

注意:我想在不修改表结构的情况下执行此操作。

Answer 1

为了实现 Eloquent 关系，您需要在Transection 表中添加另一列。示例:

      quarters                    transactions
 _________ _________    _________ ___________  ____________
|   name  |  desc   |  |   id    | quarter_id |    date    |
 _________ _________    _________ ___________  ____________
|     1   | Jan-Mar |  |     1   |      2     | 2016-04-01 |
|     2   | Apr-Jun |  |     2   |      2     | 2016-05-01 |
|     3   | Jul-Sep |  |     3   |      3     | 2012-07-21 |
|     4   | Oct-Dec |  |     4   |      1     | 2014-01-31 |
 _________ _________    _________ ___________ ______________

在此架构中，quarter_id 是表quarter_table 的捕获。现在您可以在模型中定义 Eloquent 关系，如下所示:

交易.php

public function quarter(){
    return $this->belongsTo('App\Models\Quarters') ;
}

Quarters.php

public function transactions(){
    return $this->hasMany('App\Models\Transactions') ;
}

Controller

$transactions = Transactions::where('quarter_id', $someValue)->get()

or

$transactions = Transactions::with('quarter')->get();