與額外列查詢的多對多關係休眠

我在Hibernate中成功建立了一個@ManyToMany關係，併成功添加了一列，如下所示。與額外列查詢的多對多關係休眠

Activity.class

@Entity 
@Table(name = "Activity") 
public class Activity { 

    @Id 
    @GeneratedValue 
    private int actId; 

    @OneToMany(fetch = FetchType.EAGER, mappedBy = "pk.activity", 
      cascade = { CascadeType.ALL, CascadeType.REMOVE }) 
    private Set<ActivityRepairMap> activityRepairMaps = new HashSet<ActivityRepairMap>(); 

    @NotEmpty 
    private String actTurno; 

    @NotEmpty 
    private String actTexto; 

    private String actFhc;  

    public Activity() { 
    }  
    // Getters and Setters 
}

Repair.class

@Entity 
@Table(name = "Repair2") 
public class Repair { 

    @Id 
    @GeneratedValue 
    private int repId; 

    @OneToMany(fetch = FetchType.EAGER, mappedBy = "pk.repair") 
    private Set<ActivityRepairMap> activityRepairMaps = new HashSet<ActivityRepairMap>(); 

    @NotEmpty(message=Constants.EMPTY_FIELD) 
    private String repNombre; 

    private Integer repCant; 

    public Repair() { 
    }  
    // Getters and Setters 
}

ActivityRepairMap.class

@Entity 
@Table(name="ActivityRepairMap") 
@AssociationOverrides({ 
    @AssociationOverride(name="pk.activity", [email protected](name="actId")),  
    @AssociationOverride(name="pk.repair", [email protected](name="repId")) 
    }) 
public class ActivityRepairMap { 

    private ActivityRepairId pk = new ActivityRepairId(); 
    private Integer actRepCant; 

    @EmbeddedId 
    public ActivityRepairId getPk() { 
     return pk; 
    } 

    public void setPk(ActivityRepairId pk) { 
     this.pk = pk; 
    } 

    @Transient 
    public Activity getActivity() { 
     return getPk().getActivity(); 
    } 

    public void setActivity(Activity activity) { 
     getPk().setActivity(activity); 
    } 

    @Transient 
    public Repair getRepair() { 
     return getPk().getRepair(); 
    } 

    public void setRepair(Repair repair) { 
     getPk().setRepair(repair); 
    } 

    @Column(name="actRepCant") 
    public Integer getActRepCant() { 
     return actRepCant; 
    } 

    public void setActRepCant(Integer actRepCant) { 
     this.actRepCant = actRepCant; 
    } 

    public ActivityRepairMap(){ 

    }  
    // hashCode and equals methods 
}

ActivityRepairId

@Embeddable 
public class ActivityRepairId implements Serializable{ 

    private static final long serialVersionUID = -776429030880521951L; 
    private Activity activity; 
    private Repair repair; 

    @ManyToOne 
    public Activity getActivity() { 
     return activity; 
    } 

    public void setActivity(Activity activity) { 
     this.activity = activity; 
    } 

    @ManyToOne 
    public Repair getRepair() { 
     return repair; 
    } 

    public void setRepair(Repair repair) { 
     this.repair = repair; 
    }  
    // hashCode and equals method 
}

我的問題是我無法查詢所有的維修特定活動使用。我已經在MySQL Workbench中檢查過存儲在數據庫中的數據是否正確。如果有人能夠使用HQL或Criteria解釋我，我將不勝感激，我該如何實現這一點。

非常感謝。

來源

2014-11-09 abraham.ramirez

在SQL這應該是：

SELECT 
    r.* 
FROM 
    repair r 
LEFT JOIN 
    activity_repair ar 
    ON 
     ar.repair_id = r.id 
WHERE 
    ar.activity_id = ?

現在，它仍然可能是一個activity與兩個repair連接一起，儘管你可能會在結果列表中得到一些修理兩次。你可以簡單地使用SELECT DISTINCT r.*來解決這個問題，或者使用子查詢。

在JPQL中，查詢應該與上面的SQL基本相同。

SELECT 
    r 
FROM 
    Repair r 
WHERE 
    r.activityRepairMaps.pk.activity = ?

如果你需要一個連接：

SELECT 
    r 
FROM 
    Repair r 
JOIN 
    ActivityRepairMap arm 
WHERE 
    arm.pk.activity = ?

也許你需要你的ActivityRepairMaps類中使用@MapsId。（我現在還沒有做JPQL一段時間）

據我記得，你不應該使用你的@EmbeddedId類中的實體，而是使用相應類的原始@Id類型。而不是Repair和Activity，您應該使用int和int。

來源

2014-11-09 05:05:40

與額外列查詢的多對多關係休眠

回答

相關問題