Hibernate如何映射关联另一复合主键的复合主键实体

报错的核心原因是Role实体使用包含siteId、id两个字段的复合主键CommonId，因此关联Role时需要两个列才能定位唯一实例，而原有映射只提供了role_id一个列，导致Hibernate校验不通过。

修改方案 #

1. 无需调整的代码 #

UserSiteRoleId嵌入式主键定义完全符合表结构，可以保留原有逻辑：

@Embeddable
public class UserSiteRoleId implements Serializable {

    @Type(type = "pg-id-uuid")
    @Column(columnDefinition = "uuid", updatable = false)
    private UUID userId;

    @Type(type = "pg-id-uuid")
    @Column(name = "site_id", columnDefinition = "uuid", updatable = false)
    private UUID siteId;

    @Type(type = "pg-id-uuid")
    @Column(name = "role_id", columnDefinition = "uuid", updatable = false)
    private UUID roleId;
}

2. 调整UserSiteRole实体的Role关联逻辑 #

核心修改点是用@JoinColumns指定双外键映射，复用已有的site_id字段避免重复映射：

@Entity
@Table(name = "user_site_roles", schema = "core")
@Data
@TypeDefs({
        @TypeDef(name = "pg-id-uuid", typeClass = PostgresIdUUIDType.class)
})
public class UserSiteRole extends AuditCreated implements Serializable {

    @EmbeddedId
    private UserSiteRoleId userSiteRoleId;

    @ManyToOne
    @MapsId("userId")
    @JoinColumn(name = "user_id", columnDefinition = "uuid", nullable = false)
    @OnDelete(action = OnDeleteAction.CASCADE)
    private User user;

    @ManyToOne
    @MapsId("siteId")
    @JoinColumn(name = "site_id", columnDefinition = "uuid", nullable = false)
    @OnDelete(action = OnDeleteAction.CASCADE)
    private Site site;

    // 仅修改Role关联部分即可
    @ManyToOne
    @MapsId("roleId")
    @JoinColumns(value = {
            @JoinColumn(name = "site_id", referencedColumnName = "site_id", insertable = false, updatable = false),
            @JoinColumn(name = "role_id", referencedColumnName = "id", nullable = false)
    })
    @OnDelete(action = OnDeleteAction.CASCADE)
    private Role role;

}

关键说明 #

• 用@JoinColumns指定两个外键列，完全匹配外键约束user_site_roles_role_id_fkey的定义，对应roles表的复合主键
• site_id列已经被Site关联的@MapsId("siteId")映射，因此设置insertable = false, updatable = false避免重复映射冲突
• 持久化UserSiteRole实例时，只需正常赋值site、user、role属性，Hibernate会自动填充UserSiteRoleId的三个主键字段，无需手动设置
• 你提供的user_site_roles建表脚本中，user_id外键定义末尾缺少逗号，执行前需要补充修正，避免建表失败

内容的提问来源于stack exchange，提问作者arkhadi