java - 使用 JPA 创建与实体父类(super class)的关联

Question

我有一个简单的实体类层次结构，如下所示:

Permissable  (super class)
\
 PermissableResource (sub class)

They are persisted in a table like so:

Permissable
-------------
id          PK
resource    FK Resource(resourceId) 

I have another entity called Resource that I want to create an association with. It is persisted in a table like so:

Resource
-------------
resourceId    PK

In my PermissableResource class, I create the association like so:

@JoinColumn(name="resource", referencedColumnName="resourceId")
@ManyToOne
Resource resource;

问题出在 Resource 类上。我想要引用父类(super class) Permissable 而不是子类 PermissableResource。我尝试像这样创建关联:

@OneToOne(mappedBy="resource", cascade= CascadeType.ALL, targetEntity=PermissableResource.class)
private Permissable permissiable;

但这会导致部署时出现以下错误:

Exception Description: The attribute [permissiable] in entity class [class com.dv.oa.model.entity.resource.Resource] has a mappedBy value of [resource] which does not exist in its owning entity class [class com.dv.oa.model.entity.permission.permissable.Permissable]. If the owning entity class is a @MappedSuperclass, this is invalid, and your attribute should reference the correct subclass.. Please see server.log for more details.

它在Permissable中查找关联，而不是在PermissableResource中查找

我认为，由于我使用了 @OneToOne 的 targetEntity 属性并将其指向 PermissableResource.class 这会起作用。如何在我的实体中保留父类(super class)引用，但将其映射到子类？

Answer 1

我认为问题在于，在 PermissableResource 中，您定义了一个 @ManyToOne 关系，而在 Resource 类中，您定义了一个 @OneToOne。尝试用 @OneToMany 替换后者。