两个实体之间的共享主键不工作

Question

我创建了两个实体Teacher和Detail，代码片段如下所示

Teacher.java

@Entity
@Table(name = "teacher")
public class Teacher implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private long id;
    @Column(name = "name")
    private String name;
    @Column(name = "age")
    private int age;

    @OneToOne(mappedBy = "teacher", cascade = CascadeType.ALL)
    private Detail detail;

    public Teacher() {
    }

    public Teacher(String name, int age) {
        this.name = name;
        this.age = age;
    }
//getter and setter
}

Detail.java

@Entity
@Table(name = "detail")
public class Detail implements Serializable {

    @Id
    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "id")
    private Teacher teacher;
    @Column(name = "subjects")
    private String subjects;

    public Detail() {
    }

    public Detail(String subjects) {
        this.subjects = subjects;
    }
//getter and setter
}

我正在尝试使用共享主键概念实现一对一映射但是当我执行控制器时，只有老师 table 正在更新值

try {
    Teacher teacher=new Teacher("xyz",23);
    Detail detail=new Detail("Java,c,c++");

    teacher.setDetail(detail);
    session.beginTransaction();
    session.save(teacher);
    session.getTransaction().commit();
    model.addAttribute("added", "data inserted");
    session.close();
}

仅执行教师 table 后更新为指定的 values.Detail table 仍然显示为空

Answer 1

它并不是那样工作的。您的 Detail 中仍然需要 id 字段，因此添加：

@Id
private long id;

给你的 Deatail class.

并且 - 正如评论所建议的那样 - 将字段 Teacher 中的 @Id 注释替换为 @MapsId。这样 Teacher 的 id 被映射到 Detail 的 id 但只有当你也将老师设置为细节时 - 你总是需要设置关系的双方 - 如：

teacher.setDetail(detail);
detail.setTeacher(teacher);

两个实体之间的共享主键不工作

Shared Primary Key between two Entities Not Working

orm

spring

hibernate

jpa

hibernate-mapping