使用Criteria API的Hibernate向数据库发送了太多查询
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我的印象是，通过提取hibernate可以减少查询次数，但显然情况并非如此。
这是我的根类：
public class Ereturn {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String globalId;
private String rma;
@ManyToOne
@JoinColumn(name = "shipper")
private User shipper = new User("", UserType.SHIPPER);
@ManyToOne
@JoinColumn(name = "consignee")
private User consignee;
@ManyToOne
@JoinColumn(name = "carrier")
private User carrier = new User("", UserType.CARRIER);
@JsonManagedReference(value="ereturn-parcel")
@OneToMany(mappedBy = "ereturn", fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
private List<Parcel> parcels = new ArrayList<>();
@JsonManagedReference(value="ereturn-productItems")
@OneToMany(mappedBy = "ereturn", fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
private List<ProductItem> productItems = new ArrayList<>();
...
}
请注意我的所有关系都是双向的
这是我的标准API查询：
CriteriaBuilder builder = em.getCriteriaBuilder();
CriteriaQuery<Ereturn> criteria = builder.createQuery( Ereturn.class );
Root<Ereturn> er = criteria.from(Ereturn.class);
er.fetch("shipper");
er.fetch("carrier");
er.fetch("consignee");
er.fetch("productItems");
criteria.select( er );
boolean disabled = false;
List<Predicate> predicates = new ArrayList<>();
predicates.add(builder.equal(er.get( "disabled" ), disabled));
predicates.add(builder.isNotNull( er.get( "scanDateTime" )));
predicates.add(builder.equal( er.get( "status" ), ReturnStatus.RECEIVED));
criteria.where(
builder.and(predicates.toArray(new Predicate[predicates.size()]))
);
ers = em.createQuery(criteria).getResultList();
这是发送到数据库的查询：
Hibernate:
select
ereturn0_.id as id1_1_0_,
user1_.id as id1_7_1_,
user2_.id as id1_7_2_,
user3_.id as id1_7_3_,
productite4_.id as id1_6_4_,
ereturn0_.barcode as barcode2_1_0_,
ereturn0_.carrier as carrier27_1_0_,
ereturn0_.consignee as consign28_1_0_,
ereturn0_.consigneeFirstName as consigne3_1_0_,
ereturn0_.consigneeLastName as consigne4_1_0_,
ereturn0_.creationtime as creation5_1_0_,
ereturn0_.disabled as disabled6_1_0_,
ereturn0_.dispatchedDate as dispatch7_1_0_,
ereturn0_.failedReturnPOBoxPrivateBag as failedRe8_1_0_,
ereturn0_.globalCondition as globalCo9_1_0_,
ereturn0_.globalId as globalI10_1_0_,
ereturn0_.groupName as groupNa11_1_0_,
ereturn0_.invoice as invoice12_1_0_,
ereturn0_.notes as notes13_1_0_,
ereturn0_.pickupDateTime as pickupD14_1_0_,
ereturn0_.pickupDateTimeOffset as pickupD15_1_0_,
ereturn0_.pieces as pieces16_1_0_,
ereturn0_.processedByShipper as process17_1_0_,
ereturn0_.reasonToReturn as reasonT18_1_0_,
ereturn0_.returnAction as returnA19_1_0_,
ereturn0_.returnMethod as returnM20_1_0_,
ereturn0_.returned as returne21_1_0_,
ereturn0_.rma as rma22_1_0_,
ereturn0_.scanDateTime as scanDat23_1_0_,
ereturn0_.shipper as shipper29_1_0_,
ereturn0_.status as status24_1_0_,
ereturn0_.trackingNumber as trackin25_1_0_,
ereturn0_.weight as weight26_1_0_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_,
user2_.accName as accName2_7_2_,
user2_.accNum as accNum3_7_2_,
user2_.address as address4_7_2_,
user2_.bankName as bankName5_7_2_,
user2_.branchName as branchNa6_7_2_,
user2_.bsb as bsb7_7_2_,
user2_.city as city8_7_2_,
user2_.contactNumber as contactN9_7_2_,
user2_.country as country10_7_2_,
user2_.disabled as disable11_7_2_,
user2_.email as email12_7_2_,
user2_.firstName as firstNa13_7_2_,
user2_.importEnabled as importE14_7_2_,
user2_.labelApiUrl as labelAp15_7_2_,
user2_.lastName as lastNam16_7_2_,
user2_.password as passwor17_7_2_,
user2_.pickupApiUrl as pickupA18_7_2_,
user2_.pobox as pobox19_7_2_,
user2_.postalcode as postalc20_7_2_,
user2_.secondContactNumber as secondC21_7_2_,
user2_.state as state22_7_2_,
user2_.type as type23_7_2_,
user2_.web as web24_7_2_,
user3_.accName as accName2_7_3_,
user3_.accNum as accNum3_7_3_,
user3_.address as address4_7_3_,
user3_.bankName as bankName5_7_3_,
user3_.branchName as branchNa6_7_3_,
user3_.bsb as bsb7_7_3_,
user3_.city as city8_7_3_,
user3_.contactNumber as contactN9_7_3_,
user3_.country as country10_7_3_,
user3_.disabled as disable11_7_3_,
user3_.email as email12_7_3_,
user3_.firstName as firstNa13_7_3_,
user3_.importEnabled as importE14_7_3_,
user3_.labelApiUrl as labelAp15_7_3_,
user3_.lastName as lastNam16_7_3_,
user3_.password as passwor17_7_3_,
user3_.pickupApiUrl as pickupA18_7_3_,
user3_.pobox as pobox19_7_3_,
user3_.postalcode as postalc20_7_3_,
user3_.secondContactNumber as secondC21_7_3_,
user3_.state as state22_7_3_,
user3_.type as type23_7_3_,
user3_.web as web24_7_3_,
productite4_.disabled as disabled2_6_4_,
productite4_.ereturn as ereturn18_6_4_,
productite4_.expirationDate as expirati3_6_4_,
productite4_.feedback as feedback4_6_4_,
productite4_.forward as forward5_6_4_,
productite4_.groupName as groupNam6_6_4_,
productite4_.location as location7_6_4_,
productite4_.lotNumber as lotNumbe8_6_4_,
productite4_.lotReceivedDate as lotRecei9_6_4_,
productite4_.lotStatus as lotStat10_6_4_,
productite4_.notes as notes11_6_4_,
productite4_.price as price12_6_4_,
productite4_.processed as process13_6_4_,
productite4_.product as product19_6_4_,
productite4_.quantity as quantit14_6_4_,
productite4_.quarantine as quarant15_6_4_,
productite4_.reserve as reserve16_6_4_,
productite4_.returnAction as returnA17_6_4_,
productite4_.ereturn as ereturn18_6_0__,
productite4_.id as id1_6_0__
from
ereturn ereturn0_
inner join
user user1_
on ereturn0_.shipper=user1_.id
inner join
user user2_
on ereturn0_.carrier=user2_.id
inner join
user user3_
on ereturn0_.consignee=user3_.id
inner join
product_item productite4_
on ereturn0_.id=productite4_.ereturn
where
ereturn0_.disabled=?
and (
ereturn0_.scanDateTime is not null
)
and ereturn0_.status=?
Hibernate:
select
productdef0_.id as id1_5_0_,
productdef0_.description as descript2_5_0_,
productdef0_.disabled as disabled3_5_0_,
productdef0_.height as height4_5_0_,
productdef0_.hsCode as hsCode5_5_0_,
productdef0_.length as length6_5_0_,
productdef0_.productNumber as productN7_5_0_,
productdef0_.serialNumber as serialNu8_5_0_,
productdef0_.shipper as shipper12_5_0_,
productdef0_.sku as sku9_5_0_,
productdef0_.weight as weight10_5_0_,
productdef0_.width as width11_5_0_,
user1_.id as id1_7_1_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_
from
product_definition productdef0_
left outer join
user user1_
on productdef0_.shipper=user1_.id
where
productdef0_.id=?
Hibernate:
select
productdef0_.id as id1_5_0_,
productdef0_.description as descript2_5_0_,
productdef0_.disabled as disabled3_5_0_,
productdef0_.height as height4_5_0_,
productdef0_.hsCode as hsCode5_5_0_,
productdef0_.length as length6_5_0_,
productdef0_.productNumber as productN7_5_0_,
productdef0_.serialNumber as serialNu8_5_0_,
productdef0_.shipper as shipper12_5_0_,
productdef0_.sku as sku9_5_0_,
productdef0_.weight as weight10_5_0_,
productdef0_.width as width11_5_0_,
user1_.id as id1_7_1_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_
from
product_definition productdef0_
left outer join
user user1_
on productdef0_.shipper=user1_.id
where
productdef0_.id=?
Hibernate:
select
productdef0_.id as id1_5_0_,
productdef0_.description as descript2_5_0_,
productdef0_.disabled as disabled3_5_0_,
productdef0_.height as height4_5_0_,
productdef0_.hsCode as hsCode5_5_0_,
productdef0_.length as length6_5_0_,
productdef0_.productNumber as productN7_5_0_,
productdef0_.serialNumber as serialNu8_5_0_,
productdef0_.shipper as shipper12_5_0_,
productdef0_.sku as sku9_5_0_,
productdef0_.weight as weight10_5_0_,
productdef0_.width as width11_5_0_,
user1_.id as id1_7_1_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_
from
product_definition productdef0_
left outer join
user user1_
on productdef0_.shipper=user1_.id
where
productdef0_.id=?
Hibernate:
select
productdef0_.id as id1_5_0_,
productdef0_.description as descript2_5_0_,
productdef0_.disabled as disabled3_5_0_,
productdef0_.height as height4_5_0_,
productdef0_.hsCode as hsCode5_5_0_,
productdef0_.length as length6_5_0_,
productdef0_.productNumber as productN7_5_0_,
productdef0_.serialNumber as serialNu8_5_0_,
productdef0_.shipper as shipper12_5_0_,
productdef0_.sku as sku9_5_0_,
productdef0_.weight as weight10_5_0_,
productdef0_.width as width11_5_0_,
user1_.id as id1_7_1_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_
from
product_definition productdef0_
left outer join
user user1_
on productdef0_.shipper=user1_.id
where
productdef0_.id=?
Hibernate:
select
productdef0_.id as id1_5_0_,
productdef0_.description as descript2_5_0_,
productdef0_.disabled as disabled3_5_0_,
productdef0_.height as height4_5_0_,
productdef0_.hsCode as hsCode5_5_0_,
productdef0_.length as length6_5_0_,
productdef0_.productNumber as productN7_5_0_,
productdef0_.serialNumber as serialNu8_5_0_,
productdef0_.shipper as shipper12_5_0_,
productdef0_.sku as sku9_5_0_,
productdef0_.weight as weight10_5_0_,
productdef0_.width as width11_5_0_,
user1_.id as id1_7_1_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_
from
product_definition productdef0_
left outer join
user user1_
on productdef0_.shipper=user1_.id
where
productdef0_.id=?
Hibernate:
select
productdef0_.id as id1_5_0_,
productdef0_.description as descript2_5_0_,
productdef0_.disabled as disabled3_5_0_,
productdef0_.height as height4_5_0_,
productdef0_.hsCode as hsCode5_5_0_,
productdef0_.length as length6_5_0_,
productdef0_.productNumber as productN7_5_0_,
productdef0_.serialNumber as serialNu8_5_0_,
productdef0_.shipper as shipper12_5_0_,
productdef0_.sku as sku9_5_0_,
productdef0_.weight as weight10_5_0_,
productdef0_.width as width11_5_0_,
user1_.id as id1_7_1_,
user1_.accName as accName2_7_1_,
user1_.accNum as accNum3_7_1_,
user1_.address as address4_7_1_,
user1_.bankName as bankName5_7_1_,
user1_.branchName as branchNa6_7_1_,
user1_.bsb as bsb7_7_1_,
user1_.city as city8_7_1_,
user1_.contactNumber as contactN9_7_1_,
user1_.country as country10_7_1_,
user1_.disabled as disable11_7_1_,
user1_.email as email12_7_1_,
user1_.firstName as firstNa13_7_1_,
user1_.importEnabled as importE14_7_1_,
user1_.labelApiUrl as labelAp15_7_1_,
user1_.lastName as lastNam16_7_1_,
user1_.password as passwor17_7_1_,
user1_.pickupApiUrl as pickupA18_7_1_,
user1_.pobox as pobox19_7_1_,
user1_.postalcode as postalc20_7_1_,
user1_.secondContactNumber as secondC21_7_1_,
user1_.state as state22_7_1_,
user1_.type as type23_7_1_,
user1_.web as web24_7_1_
from
product_definition productdef0_
left outer join
user user1_
on productdef0_.shipper=user1_.id
where
productdef0_.id=?
问题：如何更改标准API以减少发送到数据库的查询数量？
注意：理想情况下，我只想发送1个查询
答案
你在实体中有太多的EAGERs。尝试标记为LAZY：
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "shipper")
private User shipper = new User("", UserType.SHIPPER);
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "consignee")
private User consignee;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "carrier")
private User carrier = new User("", UserType.CARRIER);
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