问题描述
我需要插入一个具有关联的实体.
I need to insert an entity which has associations.
如果我已经拥有关联实体的 FK，有没有办法将主要实体插入到仅填充 FK 的数据库中?
If I already have the FK's of the associated entities, is there a way to insert the primary entity into the db with just the FK's populated?
或者我总是必须
- 通过 FK 检索关联实体，
- 填充涉及关联的主要实体的属性，
- 然后调用persist方法.
推荐答案
你想要一个 引用代理
假设我有帖子和标签.一个帖子有很多标签.我从用户那里得到了一堆标签，他们检查了一堆复选框.
Let's say I have Posts and Tags. A Post hasMany Tags. I get a bunch of tags from the user, who checked a bunch of checkboxes.
以下内容将向现有帖子添加标签，而无需先获取每个标签实体.它通过使用由 EntityManager::getReference() 生成的引用代理来实现:
The following would add tags to an existing post, without fetching each tag entity first. It does this by using reference proxies, generated by EntityManager::getReference():
$tag_ids = $_POST['tag_id']; // an array of integers representing tag IDs.
$post = $em->getRepository('Post')->find($post_id); // returns a Post entity.
foreach($tags_ids as $tid){
$post->addTag($em->getReference('Tag',$tid));
}
$em->persist($post);
$em->flush();
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