[英]Can JPQL retrieve the record which has no reference record?
I would like to retrieve the Reservation
which has no reference ReservationInstance
in DB by JPQL
query. 我想找回
Reservation
不具有参考ReservationInstance
在DB JPQL
查询。 ReservationInstance
entity have Reservation
entity. ReservationInstance
实体具有Reservation
实体。 It is OneToOne
unidirectional. OneToOne
是单向的。
Reservation Table 预订表
ID NAME
0001 AAA
0002 BBB
0003 CCC
0004 DDD
ReservationInstance Table ReservationInstance表
ID SOME_COLUMN RESERVATION_ID
0001 somedata 0004
How can I retrieve the Reservation
list (For AAA, BBB and CCC) which has no ReservationInstance
reference? 如何检索没有
ReservationInstance
引用的Reservation
列表(对于AAA,BBB和CCC)?
My Entities 我的实体
public class Reservation implements Serializable {
.....
private String id;
.....
private String name;
//getter and setter
}
public class ReservationInstance implements Serializable {
....
private String id;
....
private Date fromTime;
....
private Date toTime;
@OneToOne
@JoinColumn(name = "RESERVATION_ID", referencedColumnName = "ID")
private Reservation reservation;
}
Update Post 更新帖子
I used the query as below 我使用了如下查询
SELECT r FROM Reservation r LEFT JOIN ReservationInstance ri WHERE ri.reservation IS NULL
I get the exception 我得到了例外
[EL Severe]: 2012-12-18 16:37:02.817--ServerSession(1733641680)--Local Exception Stack:
Exception [EclipseLink-8023] (Eclipse Persistence Services - 2.1.2.v20101206-r8635): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Syntax error parsing the query [Reservation.findAbandonedReservation: SELECT r FROM Reservation r LEFT JOIN ReservationInstance ri WHERE ri.reservation.id IS
NULL].
Internal Exception: org.eclipse.persistence.internal.libraries.antlr.runtime.EarlyExitException
at org.eclipse.persistence.exceptions.JPQLException.syntaxError(JPQLException.java:352)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.handleRecognitionException(JPQLParser.java:350)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.addError(JPQLParser.java:242)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.reportError(JPQLParser.java:359)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.joinAssociationPathExpression(JPQLParser.java:11880)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.join(JPQLParser.java:11488)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.identificationVariableDeclaration(JPQLParser.java:11302)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.fromClause(JPQLParser.java:11164)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.selectStatement(JPQLParser.java:355)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.document(JPQLParser.java:275)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.parse(JPQLParser.java:130)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.buildParseTree(JPQLParser.java:91)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:207)
at org.eclipse.persistence.internal.jpa.JPAQuery.processJPQLQuery(JPAQuery.java:106)
at org.eclipse.persistence.internal.jpa.JPAQuery.prepare(JPAQuery.java:90)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:509)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:470)
at org.eclipse.persistence.internal.sessions.AbstractSession.processJPAQueries(AbstractSession.java:1815)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.initializeDescriptors(DatabaseSessionImpl.java:409)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.postConnectDatasource(DatabaseSessionImpl.java:666)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:615)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:228)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:389)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:164)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:221)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:209)
at org.ace.mrbs.ost.comp.reservation.persistence.ReservationDAO.deleteAbandonedReservation(ReservationDAO.java:110)
at org.ace.mrbs.ost.comp.reservation.persistence.ReservationDAO.main(ReservationDAO.java:130)
Caused by: org.eclipse.persistence.internal.libraries.antlr.runtime.EarlyExitException
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.joinAssociationPathExpression(JPQLParser.java:11868)
... 23 more
MY first choice would be to make the relation Bi-Directional. 我的第一选择是建立双向关系。
Turns out LEFT JOIN with ON will only be supported in JPA 2.1 so I suggest something like this: 原来只有JPA 2.1支持LEFT JOIN ON,所以我建议像这样:
SELECT r FROM Reservation r WHERE r IS NOT IN (SELECT ri.reservation FROM ReservationInstance ri)
Not 100% sure this works, if not try using r.id IS NOT IN
some query the returns the ids. 不是100%肯定这是有效的,如果没有尝试使用
r.id IS NOT IN
某些查询中返回ids。
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