Question

我有3个表：需求，产品和接收。为了链接需求和接收，我使用接收表而不是数据透视表（即demand_receive）的以下模式。让接收表的实例如下所示。

|**id** | **demand_id** | **receive_note** | **receive_date** |
|R1     |D2             |                  |10/29/2015        |
|R2     |D2             |                  |10/30/2015        |

数据透视表 demand_product 如下所示。

 |**demand_id** |**product_id** |**demand_quantity** |
 |D2            |P1             |100                 |
 |D2            |P2             |500                 |
 |D2            |P3             |1000                |

为追踪需求的接收产品，我制作了数据透视表 product_receive ，如下所示。

 |**receive_id** |**product_id** |**receive_quantity** |
 |R1             |P1             |50                   |
 |R2             |P1             |40                   |
 |R2             |P2             |500                  |

在这里，我试图追踪部分接收需求。我真正想要的是找到给定需求ID的单个产品的总接收数量，以便结果可用于控制视图中的接收数量（例如total_received_quantity）。

例如：

for demand id D2, 
total_receive_quantity of P1=90
total_receive_quantity of P2=500
total_receive_quantity of P3=0

如何在laravel中获得以上答案？提前谢谢。

Answer 1

应该可以这样做：

class Demand extends Model
{
    public function receives() {
        return $this->hasMany('App\Receive')
    }

    public function total_received_quantity($product_id) {
        $tally = 0;
        $receives = $this->receives;
        foreach ($receives as $receive) {
            $product_receives = $receive->product_receives;
            foreach ($product_receives as $product_receive) {
                 if ($product_receive->product->id == $product_id){
                     $tally = $tally + $product_receive->product->quantity;
                }
            }
        }
        return $tally;
    }
}

class Receive extends Model
{
    public function product_receives() {
        return $this->hasMany('App/Product_receive');
    } 
}

class Product_receive extends Model
{
    public function product() {
        return $this->belongsTo('App\Product');
    }
}

在laravel 5

1 个答案: