主从表与复合主键

主表的主键是从表的一个复合主键

主表

@Entity
@Table(name = "user")
public class User {
    @Id
    @Column(name = "ID", unique = true, nullable = false, precision = 22, scale = 0)
    private Long id;

    @Column(name = "USER_NAME", length = 100)
    private String userName;

    @Column(name = "USER_PWD", length = 100)
    private String userPwd;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "userParamKey.user")
    private List<UserParam> userParams = new ArrayList<UserParam>();
｝

从表

@Entity
@Table(name = "user_param")
public class UserParam implements Serializable {

    @EmbeddedId
    @AttributeOverrides({
            @AttributeOverride(name = "userId", column = @Column(name = "USER_ID", nullable = false)),
            @AttributeOverride(name = "openId", column = @Column(name = "OPEN_ID", nullable = false))
    })
    private UserParamKey userParamKey;

    @Column(name = "VALUE")
    private String value;
｝

从表复合主键

@Embeddable
public class UserParamKey implements Serializable {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "USER_ID", nullable = false)
    private User user;

    @Column(name = "NAME", nullable = false)
    private String name;
｝

以上