原则 2:在批处理插入引用其他实体的实体时出现奇怪的行为

问题描述

我正在尝试此处描述的批处理方法:http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/batch-processing.html

I am trying out the batch processing method described here: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/batch-processing.html

我的代码是这样的

    $limit = 10000;
    $batchSize = 20;
    $role = $this->em->getRepository('userRole')->find(1);
    for($i = 0; $i <= $limit; $i++)
    {
        $user = new EntityUser;
        $user->setName('name'.$i);
        $user->setEmail('email'.$i.'@email.blah');
        $user->setPassword('pwd'.$i);
        $user->setRole($role);
        $this->em->persist($user);
         if (($i % $batchSize) == 0) {
             $this->em->flush();
             $this->em->clear();
        }
    }

问题是，在第一次调用 em->flush() 之后$role 被分离，对于每 20 个用户，一个具有新 id 的新角色是创建，这不是我想要的

the problem is, that after the first call to em->flush() also the $role gets detached and for every 20 users a new role with a new id is created, which is not what i want

是否有针对这种情况的解决方法?我唯一能做的就是每次在循环中获取用户角色实体

is there any workaround available for this situation? only one i could make work is to fetch the user role entity every time in the loop

谢谢

推荐答案

clear() 分离实体管理器管理的所有实体，所以 $role 也分离，并尝试持久化分离的实体会创建一个新实体.

clear() detaches all entities managed by the entity manager, so $role is detached too, and trying to persist a detached entity creates a new entity.

清除后你应该重新获取角色:

You should fetch the role again after clear:

$this->em->clear();
$role = $this->em->getRepository('userRole')->find(1);

或者只是创建一个引用:

Or just create a reference instead:

$this->em->clear();
$role = $this->em->getReference('userRole', 1);

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