Symfony2 Doctrine 合并 [英] Symfony2 Doctrine merge

问题描述

我正在学习 https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/working-with-associations.html 但我无法弄清楚级联合并的作用.我在别处看到过

I am studying https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/working-with-associations.html but I cannot figure out what cascade merge does. I have seen elsewhere that

$new_object = $em->merge($object); 

基本上是基于 $object 创建一个新的托管对象.对吗?

basically creates a new managed object based on $object. Is that correct?

推荐答案

$em->merge() 用于取出已脱离实体管理器上下文的实体并重新连接它".

$em->merge() is used to take an Entity which has been taken out of the context of the entity manager and 'reattach it'.

• 如果实体从未被管理过，则合并相当于持久化.
• 如果实体被分离或序列化(可能放在缓存中)，那么合并或多或少会在数据存储中查找实体的 id，然后从那时起开始跟踪对实体的任何更改.

级联合并将此行为扩展到您要合并的实体的关联实体.这意味着更改会级联到关联，而不仅仅是被合并的实体.

Cascading a merge extends this behavior to associated entities of the one you are merging. This means that changes are cascaded to the associations and not just the entity being merged.

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