What my project have:

1. rsqlParser in order to parse complicated queries
2. Hibernate envers for audit purposes
3. Pretty stupid middle developer who don't know how to implement isNull rsql query

I have two Object with strict one-to-one relationship: object A which contains object B, and object B, which contains object A. In RDS it's looks like object B has an object_a_id field

Object_A entity class

@Entity
@Getter
@Setter
@Audited
@NoArgsConstructor
public class Object_A {

    @OneToOne(mappedBy = "object_a")
    private Object_B object_b;
}

Object_B entity

@Entity
@Getter
@Setter
@Audited
@NoArgsConstructor
public class Object_B {

    @OneToOne
    @JoinColumn(
        name = "object_a_id",
        referencedColumnName = "id",
        foreignKey = @ForeignKey(name = "object_b_object_a_fk")
    )
    private Object_A object_a;

Clearly you see that Object_B OWNS Object_A and when I try to perfom something simple like

return auditProperty.isNull();

I get

This type of relation (object_b) isn't supported and can't be used in queries

I guess I need somehow to make custom query where I add some object_b subselect beforehand but can't figure out how to write it.

CodePudding user response：

You should probably create an issue in the issue tracker(https://hibernate.atlassian.net) with a test case(https://github.com/hibernate/hibernate-test-case-templates/blob/master/orm/hibernate-orm-5/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java) that shows this limitation and ask for an improvement for this.

Usually, in ORM this is handled on the SQL level by introducing an exists subquery like:

where not exists (select 1 from object_b b where b.object_a_id = rootAlias.id)

Not sure how that works exactly in your case, but you could try to do something similar in your query.