hibernate - JPA 外键列名称

Question

@Entity
public class User {
    private String mail;
    private String password;

    @OneToMany(mappedBy="user")
    private List<UserGroup> userGroups;
}

@Embeddable
public class UserGroupPK {
    private String mail;
    private String role;
}

@Entity
public class UserGroup {
    @EmbeddedId
    private UserGroupPK id;
    private String field;

    @ManyToOne
    @MapsId("mail")
    private User user;
}

Hibernate 创建两个表:user(mail、password) 和 usergroup(user_mail、role、field)。

我需要将 user_mail 列重命名为 mail。我尝试在 UserGroupPK 中添加 @Column(name="mail") 但什么也没有。

Answer 1

我认为，以下应该有效:

@Entity
public class UserGroup {
    @EmbeddedId
    private UserGroupPK id;
    private String field;

    @ManyToOne(referencedColumnName = "mail")
    @JoinColumn(name = "mail")
    private User user;
}

参见相应段落5.1.7.1. Using a foreign key or an association table在 hibernate 文档中:

The @JoinColumn attribute is optional, the default value(s) is the concatenation of the name of the relationship in the owner side, _ (underscore), and the name of the primary key column in the owned side. In this example [user_mail] because the property name is [user] and the column id [(actually, the referencedColumnName)] of [User] is [mail].

(我替换了 [] 括号中的值。)

请注意，您的 User 实体没有主键，这可能不是一个好主意。您想实现什么目标？