4
我的课程看起来像这些。为什么同一列被选中4次?映射有什么问题?为什么Hibernate 4次选择相同的列?帮助映射?
@Entity @Table(name="CLIENTS")
public class Client implements Serializable {
@Id @GeneratedValue @Column(name="GENERATED_ID")
private Long id;
@Column(name="NAME")
private String name;
@OneToMany(cascade=CascadeType.ALL, mappedBy="client", fetch=FetchType.EAGER)
private Map<ParamPK, Param> params = new HashMap<ParamPK, Param>();
}
@Entity @Table(name="PARAMS")
public class Param implements Serializable {
@EmbeddedId
private ParamPK paramPK;
@Column(name="VALUE")
private String value;
@ManyToOne @MapsId("clientId")
private Client client;
}
@Embeddable
public class ParamPK implements Serializable {
@Column(name="PARAM_KEY")
private String key;
@Column(name="CLIENT_GENERATED_ID")
private Long clientId;
}
select生成的查询获得同一列4次。
/* from Client */
select
client0_.GENERATED_ID as GENERATED1_1_,
client0_.NAME as NAME1_
from
CLIENTS client0_
/* load one-to-many Client.params */
select
params0_.client_GENERATED_ID as client3_1_1_,
params0_.client_GENERATED_ID as client3_1_,
params0_.PARAM_KEY as PARAM1_1_,
params0_.CLIENT_GENERATED_ID as CLIENT3_1_,
params0_.client_GENERATED_ID as client3_0_0_,
params0_.PARAM_KEY as PARAM1_0_0_,
params0_.VALUE as VALUE0_0_
from
PARAMS params0_
where
params0_.client_GENERATED_ID=?
注意使用Hibernate 3.5.3。其余的样板代码已被删除为无关紧要。
你可以显示JPQL查询吗? – Jasper
不确定它会有帮助,但是您是否尝试在您的地图上添加MapKey(name =“paramPK”)注释? –
@Psy查询是普通的'em.createQuery(“来自客户端”);' – Ram