hibernate的父子查詢，不過濾兒童的FK

Question

我有一個問題，休眠查詢，該過濾從多個實體從共同父母繼承的列。

這裏是例子：

抽象父：

@Entity 
@Inheritance (strategy = InheritanceType.TABLE_PER_CLASS) 
public abstract class AItem 
{ 
     /** The id. */ 
     @Id 
     @Column (name = "pk_id") 
     private Long id; 

     /** The date of creational. */ 
     @Column (name = "c_date_created", nullable = true, columnDefinition = "timestamp with time zone") 
     private Calendar dateCreated; 

     /** The date of change. */ 
     @Column (name = "c_date_changed", nullable = true, columnDefinition = "timestamp with time zone") 
     private Calendar dateChanged; 

     /** Name of item. */ 
     @Column (name = "c_name", nullable = false) 
     private String name; 


     /** type of item. */ 
     @Column (name = "c_type", nullable = false) 
     @Enumerated (EnumType.STRING) 
     EItemType type; 
} 

孩子：

@Entity 
@Table (name = "t_product", schema = "am") 
public class CProduct extends AItem 
{ 

     @ManyToMany (fetch = FetchType.LAZY, mappedBy = "products") 
     private Set<CCampaign> campaigns; 

    ...some more attributes... 
} 
@Entity 
@Table (name = "t_service", schema = "am") 
public class CService extends AItem 
{ 

     @ManyToMany (fetch = FetchType.LAZY, mappedBy = "services") 
     private Set<CCampaign> campaigns; 

    ...some more attributes... 
} 

ccampaign：

@Entity 
@Table (name = "t_campaign", schema = "am") 
public class CCampaign 
{ 
     /** The id. */ 
     @Id 
     @SequenceGenerator (name = "T_CAMPAIGN_PKID_GENERATOR", sequenceName = "AM.T_CAMPAIGN_PK_ID_SEQ") 
     @GeneratedValue (strategy = GenerationType.AUTO, generator = "T_CAMPAIGN_PKID_GENERATOR") 
     @Column (name = "pk_id") 
     private Long id; 

     /** 
     * Products available in the campaign. 
     */ 
     @ManyToMany (fetch = FetchType.EAGER, cascade = {CascadeType.REFRESH, CascadeType.MERGE}) 
     @JoinTable (name = "t_x_campaign_product", schema = "am", joinColumns = {@JoinColumn (name = "pk_campaign", nullable = false, updatable = false)}, inverseJoinColumns = {@JoinColumn (name = "pk_item", nullable = false, updatable = false)}) 
     private Set<CProduct> products; 

     /** 
     * services available in the campaign. 
     */ 
     @ManyToMany (fetch = FetchType.EAGER, cascade = {CascadeType.REFRESH, CascadeType.MERGE}) 
     @JoinTable (name = "t_x_campaign_service", schema = "am", joinColumns = {@JoinColumn (name = "pk_campaign", nullable = false, updatable = false)}, inverseJoinColumns = {@JoinColumn (name = "pk_item", nullable = false, updatable = false)}) 
     private Set<CService> services; 
} 

我想所有（服務+產品）返回爲那個活動GN。

我有查詢

select distinct item from AItem item left join item.campaigns camp where camp.id = 5

什麼現在休眠所做的就是返回所有相關產品，而不是單一的服務。

有活動分配的服務。

當我運行查詢沒有指定camp.id然後查詢將返回服務。

可以幫助解決這個問題嗎？

Answer 1

使用Hibernate過濾器將求解問題，請參閱here參見本 annotation to filter results of a @OneToMany association