jpa - QueryException异常错误

Question

我尝试从我的表“Programme”中获得带有左联接的程序列表。之前一切正常，但是当我重新启动计算机时出现此错误

Caused by: Exception [EclipseLink-6076] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.QueryException Exception Description: Object comparisons can only be used with OneToOneMappings. Other mapping comparisons must be done through query keys or direct attribute level comparisons. Mapping: [org.eclipse.persistence.mappings.DirectToFieldMapping[idIntervention-->programme.IDINTERVENTION]] Expression: [ Query Key idIntervention Base entities.Programme] Query: ReadAllQuery(referenceClass=Programme jpql="select p from Programme p left join Intervention i on p.idIntervention =i.PROGRAMME_IDINTERVENTION where p.operationSuivante <=:d ORDER BY p.operationSuivante ASC") at org.eclipse.persistence.exceptions.QueryException.unsupportedMappingForObjectComparison(QueryException.java:1164) at org.eclipse.persistence.mappings.DatabaseMapping.buildObjectJoinExpression(DatabaseMapping.java:271) at org.eclipse.persistence.internal.expressions.RelationExpression.normalize(RelationExpression.java:805) at org.eclipse.persistence.expressions.ExpressionBuilder.normalize(ExpressionBuilder.java:265) at org.eclipse.persistence.internal.expressions.SQLSelectStatement.normalize(SQLSelectStatement.java:1414) at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.buildNormalSelectStatement(ExpressionQueryMechanism.java:549) at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.prepareSelectAllRows(ExpressionQueryMechanism.java:1708) at org.eclipse.persistence.queries.ReadAllQuery.prepareSelectAllRows(ReadAllQuery.java:785) at org.eclipse.persistence.queries.ReadAllQuery.prepare(ReadAllQuery.java:716) at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:661) at org.eclipse.persistence.queries.ObjectLevelReadQuery.checkPrepare(ObjectLevelReadQuery.java:888) at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:613) at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:194) at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:116) at org.eclipse.persistence.internal.jpa.EJBQueryImpl.(EJBQueryImpl.java:102) at org.eclipse.persistence.internal.jpa.EJBQueryImpl.(EJBQueryImpl.java:86) at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1583) at com.sun.enterprise.container.common.impl.EntityManagerWrapper.createQuery(EntityManagerWrapper.java:456) at session.ProgrammeFacade.findByDate(ProgrammeFacade.java:179) 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:483) at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1081) at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1153) at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:4695) at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:630) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822) at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582) at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:46) 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:483) at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822) at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582) at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCall(SystemInterceptorProxy.java:163) at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:140) 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:483) at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822) at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:369) at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:4667) at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4655) at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:212) ... 79 more

Answer 1

JPQL与SQL的语言不同。对实体之间的关联进行联接。它不需要ON子句。 JPQL从不使用列名。始终是实体和字段/优先级名称。

一个有效的JPQL查询(假设存在关联，但是您没有发布实体)将类似于:

select  p from Programme p 
left join p.intervention i
where p.operationSuivante <= :d 
order by p.operationSuivante asc

但是，由于您永远不会在查询中的任何地方使用 i，因此这种联接是完全无用的。