Question

我使用Netbeans生成了实体类。我的类有一个复合主键，因此Netbeans为我生成了一个额外的PK实体类。我希望在Entity类中使用NamedQuery但是作为我传递给命名查询的参数是嵌入在PK类中，NamedQuery调用失败并且查询似乎不完整。

任何人都可以提供一个示例，说明我的代码应该使用具有复合PK（@EmbeddedId关联）的NamedQuery吗？以下失败：

门面类（部分）：

@Stateless
public class EMyEntityFacade extends AbstractFacade<EMyEntity> {

public EMyEntityFacade() {
    super(EMyEntity.class);
}

//does not work
/*
private Query queryByComp1Id(int comp1Id) {
    Query query = this.getEntityManager().createNamedQuery("EMyEntity.findByComp1Id");
    query.setParameter("comp1Id", comp1Id);
    return query;
}
*/

//any nearer?
private Query queryByComp1d(int comp1Id) {
    EMyEntityPK eMyEntityPK = new EMyEntityPK();

    Query query = this.getEntityManager().createNamedQuery("EMyEntity.findByComp1Id");

    eMyEntityPK.setComp1Id(comp1Id);

    //how do I pass the eMyEntityPK through to the Entity so the query is well formed? 
    //???

    return query;
}

public List<EMyEntity> findByComp1Id(int comp1Id) {
    Query query = queryByComp1Id(comp1Id);
    return query.getResultList();
}

实体类（部分）：

@Entity
@Table(name = "my_entity")
@NamedQueries({
    @NamedQuery(name = "EMyEntity.findByComp1Id",
    query = "SELECT e FROM EMyEntity e WHERE e.eMyEntityPK.comp1Id = :comp1Id"),...)})

public class EMyEntity implements Serializable {
    private static final long serialVersionUID = 1L;
    @EmbeddedId
    protected EMyEntityPK eMyEntityPK;
    @Basic(optional = false)
    @Column(name = "inherit_from_parent")
    ...
    ...
}

PK Class（part）：

@Embeddable
public class EMyEntityPK implements Serializable {
    @Basic(optional = false)
    @Column(name = "comp1_id")
    private int comp1Id;
    @Basic(optional = false)
    @Column(name = "comp2_id")
    private int comp2Id;
    ...
    ...
}

Answer 1

您应该传递表示主键的who对象，而不仅仅是其中的一个字段。如果你需要查询部分pk，请在where子句中详细说明：where pk.fld=

具有PK实体的JPA NamedQueries

1 个答案: