Question

我遇到了hibernate查询的问题，该问题根据来自普通父级的多个实体的列进行过滤。

以下是示例：

抽象父母：

@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;
}

小孩：

@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;
}

我希望为该广告系列返回所有商品（服务+产品）。

我有查询

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

现在hibernate所做的是它返回所有相关产品，但不是单一服务。

为广告系列分配了服务。

当我在没有指定camp.id的情况下运行查询时，查询将返回服务。

可以帮助解决这个问题吗？。

Answer 1

使用Hibernate过滤器可以解决您的问题，请参阅here查看此问题的答案 annotation to filter results of a @OneToMany association

hibernate parent - child query，不要过滤孩子的FK

1 个答案: