Hibernate Annotation,如何使用@Joincolumn引用外键?

时间:2011-12-04 14:39:52

标签: hibernate annotations

我使用的是Hibernate 3.6.8。这是我的表:

CREATE TABLE UTILIZATION (
ID BIGINT NOT NULL GENERATED BY DEFAULT AS IDENTITY 
... 
FK_WORKCATEGORY SMALLINT,
CONSTRAINT PK_UTILIZATION PRIMARY KEY ( ID));

CREATE TABLE DB2ADMIN.WORKCATEGORY(
ID SMALLINT NOT NULL,
DESCRIPTION VARCHAR(50),
CONSTRAINT PK_WORKCATEGORY PRIMARY KEY(ID));

ALTER TABLE UTILIZATION ADD FOREIGN KEY (FK_WORKCATEGORY) REFERENCES WORKCATEGORY(ID); 

我的Pojos:

@Entity
@Proxy(proxyClass=IWorkCategory.class)
@Table(name="WORKCATEGORY")
public class WorkCategory extends BoBase implements Serializable, IWorkCategory{

    @Id
    private Integer Id;
    private String description;

    @Override
    public Serializable getId() {
        return Id;
    }
    @Override
    public void setId(Serializable id) {
        Id = (Integer)id;
    }
    @Override
    public String getDescription() {
        return description;
    }
    @Override
    public void setDescription(String description) {
        this.description = description;
    }   
} 

@Entity
@Proxy(proxyClass=IUtilization.class)
@Table(name="UTILIZATION")
public class Utilization extends BoBase implements Serializable, IUtilization{

    @Id     
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long Id;    

    private WorkCategory workCategory;


    @ManyToOne(fetch=FetchType.LAZY, targetEntity=WorkCategory.class)
    @JoinColumn(name="FK_WORKCATEGORY", updatable=false, insertable=false)
    public WorkCategory getWorkCategory() {
        return workCategory;
    }


    public void setWorkCategory(WorkCategory workCategory) {
        this.workCategory = workCategory;
    }
}

正如您所看到的,表格使用外键WorkCategory引用表FK_WORKCATEGORY,但在Utilization pojo中,我声明此属性的名称为workCategory。 当我为Utilization bo = UtilizationDAO.get(new Long(123))运行单元测试时,将使用列UTILIZATIO0 _。 WORKCATEGORY 生成SQL,而不是FK_WORKCATEGORY。 我已将 @JoinColumn(name =“FK_WORKCATEGORY”,放在Utilization Pojo中,但它没有帮助。 请帮我修复此错误。提前谢谢。

1 个答案:

答案 0 :(得分:5)

那是因为你把你的注释放在了吸气剂而不是放在场上。由于@Id注释放在一个字段上,Hibernate希望所有的注释都在字段上。