Doctrine中的分离实体错误

Question

我将一组实体发布到控制器，我想删除所有这些实体。但是，以下代码会引发A detached entity was found during removed MyProject\Bundle\MyBundle\Entity\MyEntity@000000004249c13f00000001720a4b59错误。我哪里错了？

$doctrineManager = $this->getDoctrine()->getManager();
foreach ($form->getData()->getEntities() as $entity) {
    $doctrineManager->merge($entity);  
    $doctrineManager->remove($entity);
}
$doctrineManager->flush();

Answer 1

您应该对处于分离状态的实体使用 merge 操作，并且您希望将它们置于托管状态。

合并应该像这样$entity = $em->merge($detachedEntity)完成。之后$entity引用合并操作返回的完全托管副本。因此，如果您的$form包含分离的实体，则应该像这样调整代码：

$doctrineManager = $this->getDoctrine()->getManager();
foreach ($form->getData()->getEntities() as $detachedEntity) {
    $entity = $doctrineManager->merge($detachedEntity);  
    $doctrineManager->remove($entity);
}
$doctrineManager->flush();

但是，如果$form不包含分离的实体，则应删除 merge 操作，如下所示：

$doctrineManager = $this->getDoctrine()->getManager();
foreach ($form->getData()->getEntities() as $entity) {
    $doctrineManager->remove($entity);
}
$doctrineManager->flush();

此图像应该可以帮助您了解实体状态转换。它取自Java Persistence API，但在Doctrine2中它大致相同。