在 CakePHP 中动态创建虚拟字段 [英] creating virtual fields on the fly in CakePHP

问题描述

我希望即时创建虚拟字段.

I wish to create virtual fields on the fly.

我的订单&订单详情就像...

My Order & Order Details are like...

//Order Model
class Order extends AppModel {
    public $name = 'Order';
    public $actsAs = array('Containable');
    public $hasMany = array(
        'OrderDetail' => array(
            'className' => 'OrderDetail',
            'foreignKey' => 'order_id',
            'dependent' => true
        ),
    );
}

//OrderDetail Model
  class OrderDetail extends AppModel {
    public $name = 'OrderDetail';
    public $actsAs = array('Containable');
    public $belongsTo = array(
        'Order' => array(
            'className' => 'Order',
            'foreignKey' => 'order_id',
            'dependent' => true
        ),
    );
}

模型关系是这样的.我正在即时创建虚拟字段，以便我可以按顺序分页计算项目数量及其成本.我知道 requestAction 的奇怪方式.他们有什么其他方式可以执行我的任务.

The model relation is like this. I am creating virtual fields on the fly so that I can count number of items and their cost in order pagination. I know the weird way of requestAction. Is their any way other I can perform my task.

我试过的代码是

        $this->Order->virtualFields['totalCost'] = 0;
        $this->Order->virtualFields['totalItem'] = 0;
        $fields = array('Order.id', 'Order.order_key', 'Order.delivery_date','COUNT(`OrderDetail`.`order_id`) AS `Order__totalItem`', 'SUM(`OrderDetail`.`cost`) AS `Order__totalCost`');         

        $this->paginate['Order'] = array("fields"=>$fields, 'conditions' => array("AND" => array($condition, "Order.status" => 3)), 'limit' => '50', 'order' => array('Order.id' => 'DESC'));

它以 mysql not found 列结束 Unknown column 'OrderDetail.order_id' in 'field list'.我没有使用递归或绑定我的模型来查找其他东西.为什么会产生这个错误?我怎样才能实现我的目标.

It ends me with the mysql not found column Unknown column 'OrderDetail.order_id' in 'field list'. I haven't put recursive or bind my model to find something else. Why this error is generated ? How can I achieve my aim.

推荐答案

您可以即时创建虚拟字段.您的语法是正确的，但您也可以这样做:

you can create virtual fields on the fly. Your syntax is correct but you can do also this way:

$this->Order->virtualFields['totalCost'] = 'SUM(`OrderDetail`.`cost`)';
$this->Order->virtualFields['totalItem'] = 'COUNT(`OrderDetail`.`order_id`)';

这里的问题是 Order 与 OrderDetail 是 HasMany 关系.在这种情况下，CakePHP 不连接表，而是进行两个查询，一个用于 Orders，一个用于 OrderDetail，然后合并记录集.

the problem here is that Order is in HasMany relationship with OrderDetail. CakePHP in this case doesn't join the tables but rather makes two queries, one for the Orders and one for the OrderDetail and then merge the recordsets.

你能做什么?

您可以对 OrderDetail 进行分页而不是 Order，并按 Order.id 对其进行分组

you can paginate OrderDetail instead of Order, and group it by Order.id

$fields = array
(
    'Order.id', 
    'Order.order_key', 
    'Order.delivery_date', 
    'Order.totalItem', 
    'Order.totalCost'
);         

$this->paginate['OrderDetail'] = array
(
    "fields"=> $fields, 
    'conditions' => array("AND" => array($condition, "Order.status" => 3)), 
    'limit' => '50', 
    'order' => array('Order.id' => 'DESC'),
    'group' => array('Order.id')
);

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