複合主キーは、TopLink

Question

は、私は1つの外部キー ComponentMarksクラスを持つことになり、複合主キーに作成する必要があります：

public class ConsolidatedMarks { 
    @Id 
    private String submission_unique_ID; 
    /****************getters and setter************/ 
    } 

エラー：

Internal Exception: javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupException 
    Exception Description: predeploy for PersistenceUnit [RDEVAL_MySQL_DB] failed. 
    Internal Exception: Exception [TOPLINK-7150] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))):  oracle.toplink.essentials.exceptions.ValidationException 
     Exception Description: Invalid composite primary key specification. The names of the primary key fields or properties in the primary key class [com.eta.entityBeans.SubQuesCompIDs] and those of the entity bean class [class com.eta.entityBeans.ComponentMarks] must correspond and their types must be the same. Also, ensure that you have specified id elements for the corresponding attributes in XML and/or an @Id on the corresponding fields or properties of the entity class. 
    java.lang.Exception: 
    Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: WebappClassLoader 
    context: /ProjectName ** 
    delegate: false 
    ----------> Parent Classloader: 
    java.net.URLClassLoader@26b418 

    Internal Exception: javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupException 
    Exception Description: predeploy for PersistenceUnit [RDEVAL_MySQL_DB] failed. 
    Internal Exception: Exception [TOPLINK-7150] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationException 
     Exception Description: Invalid composite primary key specification. The names of the primary key fields or properties in the primary key class [com.eta.entityBeans.SubQuesCompIDs] and those of the entity bean class [class com.eta.entityBeans.ComponentMarks] must correspond and their types must be the same. Also, ensure that you have specified id elements for the corresponding attributes in XML and/or an @Id on the corresponding fields or properties of the entity class. 

も ​​"@IdClass（SubQuesCompIDs.class）" でのJavaクラス "ComponentMarks" で、それはこのコンパイル・エラー・メッセージを示していた：

The attribute matching the ID class attribute consolidatedMarks does not have the correct type com.eta.entityBeans.ConsolidatedMarks 

ConsolidatedMarksは、パッケージcom.eta.entityBeansからです。

更新ComponentMarks：

@Entity 
@Table(name="component_marks") 
@IdClass(SubQuesCompIDs.class) 
public class ComponentMarks { 
    @Id 
    private String component_ID; 
    @Id 
    private String question_ID; 
    @Id 
    @Column(name="submission_unique_ID") 
    @ManyToOne(cascade=CascadeType.ALL) 
    @JoinColumn(name="submission_unique_ID") 
    private ConsolidatedMarks consolidatedMarks; 
    /****************getters and setter************/ 
    } 

更新SubQuesCompIDs：

public class SubQuesCompIDs implements Serializable{ 
    private String consolidatedMarks; 
    private String component_ID; 
    private String question_ID; 
    /****************getters and setter************/ 
    } 

今、コンパイルエラーで、2番目のエラーが来ていません。

Answer 1

これは「派生アイデンティティ」です。

あなた@IdClass次のようになります。

public class SubQuesCompIDs implements Serializable{ 

    private String consolidatedMarks; 
    private String component_ID; 
    private String question_ID; 
/****************getters and setter************/ 
} 

注@ManyToOneconsolidatedMarksフィールドに対応するフィールドが同じフィールド名を持つが、その種類はConsolidatedMarks主キーフィールドの型と一致します。

派生したアイデンティティについては、JPA 2.1仕様、セクション2.4.1で説明します。