如何在一个查询中正确地从数据库中删除一条记录？ JPA

Question

How to properly delete a record from a database in one query. For example, when an entity uses the primary key of the parent entity using the @MapsId annotation, if the parent entry is deleted, it will swear that the parent's id is used in the child entity.

Code example:

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private long id;
    private String name;
}


@Entity
public class UserDetails {
    @Id
    private long id;
    private String phone;
    @OneToOne(fetch = FetchType.LAZY)
    @MapsId
    private User user;
}

Here, when deleting a User using the JpaRepository delete method, an error will occur that the UserDetail uses the primary key User

Answer 1

For that you need to delete all foreign keys with used by primary key

or by using cascade

After that use below

In JPA we can use deleteById

or by named query

DELETE FROM EMPLOYEE WHERE ID =?1

or my native query

delete from employee where id =?1

Answer 2

First, are you sure the direction of the relation makes sense? I would have expected it to be the other way around, because the user ID and name seem to be the more basic info that you need more often.

Second, what you're doing seems like an attempt to optimize performance, because you could just as well store all the data in a single entity. Are you sure the optimization pays off? (I would guess not.) See Premature Optimization .

Third, if the relation was the other way around, you could modify the annotation to @OneToOne(cascade=CascadeType.DELETE) or @OneToOne(cascade=CascadeType.ALL) to let JPA automatically delete the other entity when the first is deleted.