當我把多對一註釋

-1

T1(
    id (pk), 
    name (varchar) 
) 

T2(
    id (pk), 
    t1_id (fk_t1), 
    number (int) 
) 

T3 (
    id (pk), 
    t2_id (fk_t2), 
    time (datetime) 
    zone (tinyint), 
    name (varchar) 
)

，這是我T3Entity

@Entity 
@Table(name="T3, schema="", catalog="dbname") 
public class T3Entity{ 
    private int id; 
    private DateTime datetime; 
    private int zone; 
    private String name; 

    @Id 
    @Column(name="id", nullable=false, insertable=true, updatable=true) 
    //GETTER/SETTERS 

    @Basic 
    @Column(name="datetime", nullable=false, insertable=true, updatable=true) 
    //GETTER/SETTERS 

    @Basic 
    @Column(name="zone", nullable=false, insertable=true, updatable=true) 
    //GETTER/SETTERS 

    @Basic 
    @Column(name="name", nullable=false, insertable=true, updatable=true) 
    //GETTER/SETTERS 

}

當我T3Entity類添加該代碼沒有主鍵的錯誤，我得到了一個錯誤

@ManyToOne(fetch=FetchType.Lazy) 
@JoinColumn(name="T2_id", referencedColumn="T2_id") 
private T2Entity t2Entity; 
//getters-setters

我得到這個錯誤

Internal Exception: javax.persistence.PersistenceException: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.EntityManagerSetupException 
Exception Description: Predeployment of PersistenceUnit [PU] failed. 
Internal Exception: Exception [EclipseLink-7161] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.ValidationException 
Exception Description: Entity class [class com.project.entity.T3Entity] has no primary key specified. It should define either an @Id, @EmbeddedId or an @IdClass. If you have defined PK using any of these annotations then make sure that you do not have mixed access-type (both fields and properties annotated) in your entity class hierarchy.

來源

2016-04-24 Em Ae

不應該這個是

@JoinColumn(name="T2_id")

，而不是

@JoinColumn(name="T2_id", referencedColumn="T2_id")

我不知道的EclipseLink，但休眠甚至不會讓我指定一個不存在的列名referencedColumn。如果你堅持，它應該是

@JoinColumn(name="T2_id", referencedColumn="id")

因此它引用一個存在的列。

來源

2016-04-26 16:07:04

當我把多對一註釋

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