Question

我有一个实体层次结构，它们在根实体中具有必须只读的关系。但是在叶子实体中，这种关系不应该有这种行为。

@Entity
class X {@Id private Long id;} //gets sets

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "TYPE")
class Root {
    @Id private Long id; //gets sets

    @ManyToOne
    @JoinColumn(name = "X_ID", nullable = false, insertable = false, updatable = false) //READ ONLY
    private X x;
}

@Entity
@DiscriminatorValue(value = "ExampleValue")
@AssociationOverrides({ //I try to override to becomes no longer read only
    @AssociationOverride(name = "x", joinColumns = {@JoinColumn(name = "X_ID", referencedColumnName = "X_ID" nullable = false)}
}
class Leaf extends Root {
}

但是当我在Leaf对象中调用实体管理器时，生成的sql不包含X_ID列信息。

Answer 1

替换此

@Entity
@DiscriminatorValue(value = "ExampleValue")
@AssociationOverrides({ //I try to override to becomes no longer read only
    @AssociationOverride(name = "x", joinColumns = {@JoinColumn(name = "X_ID", referencedColumnName = "X_ID" nullable = false)}
}
class Leaf extends Root {
}

与

 @Entity
   @DiscriminatorValue(value = "ExampleValue")
   @Table(name = "LEAF")
   public class Leaf
   {
    @Embedded
    @AssociationOverrides({
    @AssociationOverride(name = "x", joinColumns = {@JoinColumn(referencedColumnName = "X_ID" nullable = false)})
private Root root;       
}

AssociationOverrides不适用于继承中的子实体

1 个答案: