学说撷取加入

本文介绍了学说撷取加入的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 首先我会举一些伪代码的例子，然后我将解释什么是问题。让我说我有两个实体User和Phonenumber。他们的关系是一对多的。在我的UserRepository中，我可以这样做：

class UserRepository { public function getUser id，$ type） { $ users = $ this-> createQuery（SELECT u，p FROM User u JOIN u.phonenumbers p WHERE u.id =：id AND p .type =：type） - > setParameters（array（'id'=> $ id，'type'=> $ type，） - > getResult（）; return $ users [0]; } }

在我的应用程序中，如果我有这样的东西： p>

$ user = $ userRepo-> getUser（1，'home'）; var_dump（$ user-> getPhonenumbers（））; //这里phonenumbers集合是ok $ user = $ userRepo> getUser（1，'work'）; var_dump（$ user-> getPhonenumbers（））; //这里phonenumbers收藏是错误的。 //与前一个完全一样。

所以我的问题是：是否可以使用提取连接（具有不同的条件）每次正确收集？

解决方案

获取加入和过滤集合并不是很好地协同工作。以下是您应该如何做：

SELECT u，p FROM 用户u JOIN u.phonenumbers p JOIN u.phonenumbers p2 WHERE u.id =：id AND p2 .type =：type

这对第二个加入（而不是水合）应用过滤器 p2 ，这会导致正确的水合和过滤。

First I will give an example with some pseudo code and then I will explain what is the problem. Let me say I have two entities User and Phonenumber. Their relation is one-to-many. In my UserRepository I can have something like that:

class UserRepository { public function getUser($id, $type) { $users = $this->createQuery("SELECT u, p FROM User u JOIN u.phonenumbers p WHERE u.id = :id AND p.type = :type") ->setParameters(array( 'id' => $id, 'type' => $type, )) ->getResult(); return $users[0]; } }

In my app if I have something like:

$user = $userRepo->getUser(1, 'home'); var_dump($user->getPhonenumbers()); // here phonenumbers collection is ok $user = $userRepo->getUser(1, 'work'); var_dump($user->getPhonenumbers()); // Here phonenumbers collection is wrong. // It's exactly the same as the previous one.

So my questions is: Is it possible to use fetch join (with different criteria) and to get the proper collection each time?

解决方案

Fetch joining and filtering a collection are not things that work together quite well. Here's how you should do it:

SELECT u, p FROM User u JOIN u.phonenumbers p JOIN u.phonenumbers p2 WHERE u.id = :id AND p2.type = :type

This applies filtering on the second joined (and not hydrated) p2, which results in correct hydration and filtering.