Hibernate request causing unnecessary unnecessary requests

Question

I am developing an auction site. The problem is the 3 objects that I use:

• Product (has zero or many ProductBid)
• ProductBid (has zero or one ProductBidRejection)
• ProductBidRejection

I use a sleep request to get bets:

select pb from ProductBid pb left join pb.rejection pbr where pbr is null and pb.product = :product order by pb.amount desc

This generates this request (via console):

select
    productbid0_.id as id4_,
    productbid0_.amount as amount4_,
    productbid0_.bid_by as bid4_4_,
    productbid0_.date as date4_,
    productbid0_.product_id as product5_4_ 
from
    product_bids productbid0_ 
left outer join
    product_bid_rejections productbid1_ 
        on productbid0_.id=productbid1_.product_bid_id 
where
(
    productbid1_.id is null
) 
and productbid0_.product_id=?

But for each application she also receives:

select
    productbid0_.id as id3_1_,
    productbid0_.date_rejected as date2_3_1_,
    productbid0_.product_bid_id as product4_3_1_,
    productbid0_.reason as reason3_1_,
    productbid0_.rejected_by as rejected5_3_1_,
    productbid1_.id as id4_0_,
    productbid1_.amount as amount4_0_,
    productbid1_.bid_by as bid4_4_0_,
    productbid1_.date as date4_0_,
    productbid1_.product_id as product5_4_0_ 
from
    product_bid_rejections productbid0_ 
inner join
    product_bids productbid1_ 
        on productbid0_.product_bid_id=productbid1_.id 
where
    productbid0_.product_bid_id=?

These are my entities:

ProductBid

@Entity
@Table(name = "product_bids")
public class ProductBid
{
    @Column(name = "id", nullable = false)
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @JoinColumn(name = "product_id", nullable = false)
    @Index(name="product")
    @ManyToOne(fetch = FetchType.LAZY)
    private Product product;

    @Column(name = "amount", nullable = false)
    private BigDecimal amount;

    @JoinColumn(name = "bid_by", nullable = false)
    @Index(name="bidBy")
    @ManyToOne(fetch = FetchType.LAZY)
    @Fetch(FetchMode.JOIN)
    private User bidBy;

    @Column(name = "date", nullable = false)
    @Type(type = "org.joda.time.contrib.hibernate.PersistentDateTime")
    private DateTime date;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "productBid")
    private ProductBidRejection rejection;
}

ProductBidRejection

@Entity
@Table(name = "product_bid_rejections")
public class ProductBidRejection
{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false)
    private long id;

@Column(name = "reason", nullable = false, columnDefinition = "TEXT")
private String reason;

@Column(name = "date_rejected", nullable = false)
@Type(type = "org.joda.time.contrib.hibernate.PersistentDateTime")
private DateTime dateRejected;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "rejected_by", nullable = false)
private User rejectedBy;

@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "product_bid_id", nullable = false)
@Fetch(FetchMode.JOIN)
private ProductBid productBid;

} Code>

Answer 1

This is because you have it @Fetch(FetchMode.JOIN)on ProductBid. Therefore, for each of the ProductBidRejections that you retrieve, it also loads the ProductBid.

UPDATE

. pb PBR

select distinct pb from ProductBid pb left join fetch pb.rejection pbr where pbr is null and pb.product = :product order by pb.amount desc

Answer 2

HQL, .

session.createCriteria(ProductBid.class).add(Restrictions.eq("product",yourproduct)).list();

ProductBid Entity Class , EAGER ly ProductBidRejection