级联在保存数据时不起作用

Question

我有一对一的映射关系。

用户.java

public class User {

    @Id
    @SequenceGenerator(name = "userID", sequenceName = "userID")
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "userID")
    @Column(name = "id")
    private Long id;

    private String firstName;
    private String lastName;

    @Column(unique = true)
    private String username;
    private String password;

    @OneToOne(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name = "id")
    private Role role;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public Role getRole() {
        return role;
    }

    public void setRole(Role role) {
        this.role = role;
    }

    @Override
    public String toString() {
        return "User [id=" + id + ", firstName=" + firstName + ", lastName="
                + lastName + ", username=" + username + ", password="
                + password + ", role=" + role + "]";
    }

}

Roles.java

public class Role {

    @Id
    @SequenceGenerator(name = "userID", sequenceName = "userID")
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "userID")
    @Column(name = "roleId")
    private Long roleId;

    @OneToOne
    private User user;
    private Integer role;

    public Long getId() {
        return roleId;
    }

    public void setId(Long id) {
        this.roleId = id;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getRole() {
        return role;
    }

    public void setRole(Integer role) {
        this.role = role;
    }
}

我正在保存数据

public Long create(User user) {
    Long userID = super.save(user);
    return userID;
}

当我尝试保存用户实体时，我看到数据保存如下。

用户表：

    id   firstName lastName   usrename   password

     1    hello     hello      hello     hello

角色表：

    roleId      role     user_id

     1          1         NULL

你能告诉我用户表没有相互关联吗？

我需要 user_id 为 1 而不是 NULL。

这里 user 表的 id 没有映射到表 Role 的 user_id。

Answer 1

• 角色是关联的所有者，用户的@OneToOne角色根本不需要@JoinColumn：

  @Id
  @SequenceGenerator(name = "userID", sequenceName = "userID")
  @GeneratedValue(strategy = GenerationType.AUTO, generator = "userID")
  @Column(name = "id")
  private Long id;
  
  @OneToOne(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
  private Role role;
  

• 保存用户时还需要设置关联的两边：

  user.setRole(role);
  role.setUser(user);
  userDao.create(user);