删除双向 OneToOne 关系中的子实体

Question

我在一对一关系中有以下课程。

DrivingLicense.java
@Entity
@Table(name = "DRIVING_LICENSE")
public class DrivingLicense {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "LICENSE_NUMBER")
    private int licenseNumber;
    @Column(name = "DATE_OF_ISSUE")
    private Date dateOfIssue;

    @OneToOne
    @JoinColumn(name = "PERSON_ID")
    private Person person;
}

和

Person.java
@Entity
@Table(name = "PERSON")
public class Person {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "PERSON_ID")
    private int personId;
    @Column(name = "PERSON_NAME", nullable = false, length = 30)
    private String personName;

    @OneToOne(mappedBy = "person", cascade = CascadeType.ALL)
    private DrivingLicense drivingLicense;
}

现在当我尝试删除驾驶执照实体然后它没有删除它时，我很困惑，如何单独删除驾驶执照？

    entityManager.getTransaction().begin();

    DrivingLicense drivingLicense = entityManager.find(DrivingLicense.class, 6);
    entityManager.remove(drivingLicense);
    entityManager.getTransaction().commit();

更新

而不是在两个选择下删除它的触发

Hibernate: select drivinglic0_.LICENSE_NUMBER as LICENSE_NUMBER1_0_0_, drivinglic0_.DATE_OF_ISSUE as DATE_OF_ISSUE2_0_0_, drivinglic0_.PERSON_ID as PERSON_ID3_0_0_, person1_.PERSON_ID as PERSON_ID1_1_1_, person1_.PERSON_NAME as PERSON_NAME2_1_1_ from DRIVING_LICENSE drivinglic0_ left outer join PERSON person1_ on drivinglic0_.PERSON_ID=person1_.PERSON_ID where drivinglic0_.LICENSE_NUMBER=?
Hibernate: select drivinglic0_.LICENSE_NUMBER as LICENSE_NUMBER1_0_1_, drivinglic0_.DATE_OF_ISSUE as DATE_OF_ISSUE2_0_1_, drivinglic0_.PERSON_ID as PERSON_ID3_0_1_, person1_.PERSON_ID as PERSON_ID1_1_0_, person1_.PERSON_NAME as PERSON_NAME2_1_0_ from DRIVING_LICENSE drivinglic0_ left outer join PERSON person1_ on drivinglic0_.PERSON_ID=person1_.PERSON_ID where drivinglic0_.PERSON_ID=?

为什么这 2 个选择会被触发？

Answer 1

首先尝试从其各自的Person 中删除drivingLicense：

entityManager.getTransaction().begin();

DrivingLicense drivingLicense = entityManager.find(DrivingLicense.class, 6);

Person person = drivingLicense.getPerson();
person.setDrivingLicense(null);
entityManager.merge(person);

entityManager.remove(drivingLicense);

entityManager.getTransaction().commit();