那些遇到过的问题

使用JPA中的自联接从特定行组内检索行号

Tin*_*iny 7 hibernate jpa self-join

给定一个rating在MySQL数据库中命名的表.

+-------------+---------------------+------+-----+---------+----------------+
| Field       | Type                | Null | Key | Default | Extra          |
+-------------+---------------------+------+-----+---------+----------------+
| rating_id   | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| prod_id     | bigint(20) unsigned | YES  | MUL | NULL    |                |
| rating_num  | int(10) unsigned    | YES  |     | NULL    |                |
| ip_address  | varchar(45)         | YES  |     | NULL    |                |
| row_version | bigint(20) unsigned | NO   |     | 0       |                |
+-------------+---------------------+------+-----+---------+----------------+
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我需要从此表中的一组行中获取行号.在Oracle中,row_number()窗口功能是救援.

SELECT row_num 
  FROM  (SELECT row_number() over (PARTITION BY prod_id ORDER BY rating_id DESC)
         AS prod_id, rating_id, row_num FROM rating)
WHERE rating_id=? AND prod_id = ?;
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然而,JPA和MySQL都不支持窗口功能.因此,可以使用以下不同的SQL语句(基于自联接prod_id).

SELECT a.prod_id, a.rating_id, count(*) as row_number 
FROM rating a 
INNER JOIN rating b ON a.prod_id = b.prod_id AND a.rating_id <= b.rating_id
GROUP BY a.prod_id, a.rating_id
ORDER BY a.prod_id, a.rating_id DESC
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该语句返回以下结果集.

+---------+-----------+------------+
| prod_id | rating_id | row_number |
+---------+-----------+------------+
|       7 |        16 |          1 |
|       7 |         3 |          2 |
+---------+-----------+------------+
|       8 |         8 |          1 |
|       8 |         1 |          2 |
+---------+-----------+------------+
|       9 |        15 |          1 |
|       9 |        14 |          2 |
|       9 |         5 |          3 |
+---------+-----------+------------+
|      10 |        11 |          1 |
|      10 |        10 |          2 |
|      10 |         9 |          3 |
|      10 |         7 |          4 |
|      10 |         6 |          5 |
|      10 |         2 |          6 |
+---------+-----------+------------+
|      16 |        13 |          1 |
|      16 |        12 |          2 |
|      16 |         4 |          3 |
+---------+-----------+------------+
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可以rating_id使用连接中的附加条件,基于(主键)从上述结果集中检索与特定产品组相关联的行号.现在可以完全按如下方式完成查询.

SELECT a.prod_id, a.rating_id, count(*) as row_number 
FROM rating a 
INNER JOIN rating b ON a.prod_id = b.prod_id AND a.rating_id <= b.rating_id
AND a.rating_id=?
GROUP BY a.prod_id, a.rating_id
ORDER BY a.prod_id, a.rating_id DESC
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As obvious, a row number of a specific group of products can now be selected from the third column (row_number) of the result set (which will always be one row only).

The finalized query in JPA is nevertheless still troublesome. The following criteria query is insufficient to generate the above SQL statement.

CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Tuple> criteriaQuery = criteriaBuilder.createTupleQuery();
Root<Rating> root = criteriaQuery.from(entityManager.getMetamodel().entity(Rating.class));
criteriaQuery.multiselect(root.get(Rating_.product).get(Product_.prodId), root.get(Rating_.ratingId), criteriaBuilder.count(root));

Join<Rating, Rating> join = root.join(Rating_.rating, JoinType.INNER).on(criteriaBuilder.equal(root, rating));
criteriaQuery.where(criteriaBuilder.lessThanOrEqualTo(root.get(Rating_.ratingId), join.get(Rating_.ratingId)));
criteriaQuery.groupBy(root.get(Rating_.product).get(Product_.prodId), root.get(Rating_.ratingId));
criteriaQuery.orderBy(criteriaBuilder.desc(root.get(Rating_.product).get(Product_.prodId)), criteriaBuilder.desc(root.get(Rating_.ratingId)));

List<Tuple> list = entityManager.createQuery(criteriaQuery).getResultList();
Long rowNumber = list == null || list.isEmpty() ? 0L : list.get(0).get(2, Long.class);
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The JPQL corresponding to the above criteria query :

SELECT a.product.prodId, a.ratingId, COUNT(a) AS row_number
FROM Rating a INNER JOIN a.rating b ON a.ratingId=:ratingId
WHERE a.ratingId <= b.ratingId
GROUP BY a.product.prodId, a.ratingId
ORDER BY a.product.prodId, a.ratingId DESC
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Both of the above queries generate the following SQL statement.

select
    rating0_.`prod_id` as col_0_0_,
    rating0_.`rating_id` as col_1_0_,
    count(rating0_.`rating_id`) as col_2_0_ 
from
    `jboss_projectdb`.`rating` rating0_ 
inner join
    `jboss_projectdb`.`rating` rating1_ 
        on rating0_.`prod_id`=rating1_.`rating_id` 
        and (
            rating0_.`rating_id`=?
        ) 
where
    rating0_.`rating_id`<=rating1_.`rating_id` 
group by
    rating0_.`prod_id` ,
    rating0_.`rating_id` 
order by
    rating0_.`prod_id` desc,
    rating0_.`rating_id` desc
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Notice the join condition in the generated statement.

on rating0_.`prod_id`=rating1_.`rating_id`
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It should however be 

on rating0_.`prod_id`=rating1_.`prod_id`
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So, the question being is how to self join the rating table based on prod_id (which is a foreign key)?

The self join relationship in the Rating entity has been defined as follows.

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "prod_id", insertable = false, updatable = false)
private Rating rating;

@OneToMany(fetch = FetchType.LAZY, mappedBy = "rating")
private List<Rating> ratingList;
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我对使用以下特定于MySQL的特定语句从特定行组内部获取行号不感兴趣.

SELECT
    row_num 
FROM
    (SELECT @row_num := @row_num + 1 AS row_num, tbl.rating_id 
     FROM
         rating tbl, (SELECT @row_num := 0) t 
     WHERE
         tbl.prod_id=? 
     ORDER  BY
         tbl.rating_id DESC) t 
     WHERE
         rating_id = ?
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更新:

如果关系改变如下,

@JoinColumn(name = "prod_id", referencedColumnName = "prod_id", insertable = false, updatable = false)
@ManyToOne(fetch = FetchType.LAZY)
private Rating rating;

@JoinColumn(name = "prod_id", referencedColumnName = "prod_id")
@OneToMany(fetch = FetchType.LAZY)
private List<Rating> ratingList;
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Hibernate抛出以下异常.

16:43:52,609 WARNING [javax.enterprise.resource.webcontainer.jsf.lifecycle] (default task-18) javax.persistence.PersistenceException: org.hibernate.HibernateException: More than one row with the given identifier was found: entity.Rating[ratingId=null], for class: entity.Rating: service.app.exception.impl.DatabaseException: javax.persistence.PersistenceException: org.hibernate.HibernateException: More than one row with the given identifier was found: entity.Rating[ratingId=null], for class: entity.Rating
    at service.ejb.interceptors.ExceptionInterceptor.handle(ExceptionInterceptor.java:32)
    at sun.reflect.GeneratedMethodAccessor398.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.jboss.as.ee.component.ManagedReferenceLifecycleMethodInterceptor.processInvocation(ManagedReferenceLifecycleMethodInterceptor.java:89)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.jpa.interceptor.SBInvocationInterceptor.processInvocation(SBInvocationInterceptor.java:47)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
    at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:64)
    at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:83)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ee.concurrent.ConcurrentContextInterceptor.processInvocation(ConcurrentContextInterceptor.java:45)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
    at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:52)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.pool.PooledInstanceInterceptor.processInvocation(PooledInstanceInterceptor.java:51)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:275)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:327)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:239)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.invocationmetrics.WaitTimeInterceptor.processInvocation(WaitTimeInterceptor.java:43)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.security.AuthorizationInterceptor.processInvocation(AuthorizationInterceptor.java:138)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.security.SecurityContextInterceptor.processInvocation(SecurityContextInterceptor.java:100)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:64)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:66)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:54)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
    at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:636)
    at org.jboss.invocation.AccessCheckingInterceptor.processInvocation(AccessCheckingInterceptor.java:61)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
    at org.jboss.invocation.PrivilegedWithCombinerInterceptor.processInvocation(PrivilegedWithCombinerInterceptor.java:80)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
    at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:195)
    at org.jboss.as.ee.component.ViewDescription$1.processInvocation(ViewDescription.java:185)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
    at org.jboss.as.ee.component.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:73)
    at shareable.bean.ShareableService$$$view330.findRatingById(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.jboss.weld.util.reflection.Reflections.invokeAndUnwrap(Reflections.java:436)
    at org.jboss.weld.bean.proxy.EnterpriseBeanProxyMethodHandler.invoke(EnterpriseBeanProxyMethodHandler.java:127)
    at org.jboss.weld.bean.proxy.EnterpriseTargetBeanInstance.invoke(EnterpriseTargetBeanInstance.java:56)
    at org.jboss.weld.bean.proxy.InjectionPointPropagatingEnterpriseTargetBeanInstance.invoke(InjectionPointPropagatingEnterpriseTargetBeanInstance.java:67)
    at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:100)
    at shareable.bean.ShareableService$614900122$Proxy$_$$_Weld$EnterpriseProxy$.findRatingById(Unknown Source)
    at converter.RatingConverter.getAsObject(RatingConverter.java:41)
    at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:171)
    at javax.faces.component.UIViewParameter.getConvertedValue(UIViewParameter.java:437)
    at javax.faces.component.UIInput.validate(UIInput.java:975)
    at javax.faces.component.UIInput.executeValidate(UIInput.java:1248)
    at javax.faces.component.UIInput.processValidators(UIInput.java:712)
    at javax.faces.component.UIViewParameter.processValidators(UIViewParameter.java:278)
    at org.omnifaces.component.input.ViewParam.processValidators(ViewParam.java:120)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1261)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1261)
    at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1195)
    at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:78)
    at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at io.undertow.websockets.jsr.JsrWebSocketFilter.doFilter(JsrWebSocketFilter.java:129)
    at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at org.omnifaces.facesviews.FacesViewsForwardingFilter.filterExtensionLess(FacesViewsForwardingFilter.java:128)
    at org.omnifaces.facesviews.FacesViewsForwardingFilter.doFilter(FacesViewsForwardingFilter.java:89)
    at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:108)
    at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at filter.NoCacheFilter.doFilter(NoCacheFilter.java:33)
    at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at org.omnifaces.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:122)
    at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:108)
    at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
    at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
    at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
    at io.undertow.server.handlers.DisableCacheHandler.handleRequest(DisableCacheHandler.java:33)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.security.handlers.AuthenticationConstraintHandler.handleRequest(AuthenticationConstraintHandler.java:51)
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
    at io.undertow.servlet.handlers.security.ServletSecurityConstraintHandler.handleRequest(ServletSecurityConstraintHandler.java:56)
    at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
    at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
    at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: javax.persistence.PersistenceException: org.hibernate.HibernateException: More than one row with the given identifier was found: entity.Rating[ratingId=null], for class: entity.Rating
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
    at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:492)
    at org.hibernate.jpa.criteria.compile.CriteriaQueryTypeQueryAdapter.getResultList(CriteriaQueryTypeQueryAdapter.java:50)
    at shareable.bean.ShareableBean.findRatingById(ShareableBean.java:472)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.jboss.as.ee.component.ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptor.java:52)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
    at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:82)
    at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:93)
    at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:63)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
    at service.ejb.interceptors.ExceptionInterceptor.handle(ExceptionInterceptor.java:22)
    ... 133 more
Caused by: org.hibernate.HibernateException: More than one row with the given identifier was found: entity.Rating[ratingId=null], for class: entity.Rating
    at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:86)
    at org.hibernate.loader.entity.EntityLoader.loadByUniqueKey(EntityLoader.java:143)
    at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2146)
    at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:685)
    at org.hibernate.type.EntityType.resolve(EntityType.java:427)
    at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:151)
    at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:125)
    at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1132)
    at org.hibernate.loader.Loader.processResultSet(Loader.java:992)
    at org.hibernate.loader.Loader.doQuery(Loader.java:930)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:336)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:306)
    at org.hibernate.loader.Loader.loadEntity(Loader.java:2197)
    at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:60)
    at org.hibernate.loader.entity.EntityLoader.loadByUniqueKey(EntityLoader.java:143)
    at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2146)
    at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:685)
    at org.hibernate.type.EntityType.resolve(EntityType.java:427)
    at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:151)
    at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:125)
    at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1132)
    at org.hibernate.loader.Loader.processResultSet(Loader.java:992)
    at org.hibernate.loader.Loader.doQuery(Loader.java:930)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:336)
    at org.hibernate.loader.Loader.doList(Loader.java:2610)
    at org.hibernate.loader.Loader.doList(Loader.java:2593)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2422)
    at org.hibernate.loader.Loader.list(Loader.java:2417)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:501)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:371)
    at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:216)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1339)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
    at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606)
    at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483)
    ... 148 more
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criteriaQuery.multiselect(...).distinct(true);没有帮助.所以,我认为可能没有办法解决这个问题.

Dra*_*vic 1

Hibernate 完全按照映射的指示执行所有操作。该构造FROM Rating a INNER JOIN a.rating b意味着将一个评级的主键与另一个评级的外键（引用该 PK）连接起来。

要通过映射实现您想要的效果，您必须显式构造联接条件，因此JPQL 的fromand子句可能如下所示：where

SELECT ...
FROM Rating a, Rating b
WHERE a.rating.id = b.rating.id
  AND a.ratingId = :ratingId
  AND a.ratingId <= b.ratingId
GROUP BY ...
ORDER BY ...
Run Code Online (Sandbox Code Playgroud)

rating.id被翻译为prod_id列。

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