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我正在尝试使用单个命名查询来获取一组结果并计算可用数据量。我有一个命名的 JPQL 查询：

@NamedQuery(name = "query.all.absences.by.name", query = "SELECT a FROM Absence a WHERE a.name = :name")

当我获得缺席时，我正在调用这样的查询：

final Query q = em.createNamedQuery("query.all.absences.by.name");
q.setParameter("name","aRandomAbsenceName");
//maxResults and firstResult are coming as parameters, are computed in another method
q.setMaxResults(maxResults);
q.setFirstResult(firstResult);

q.getResultList()让我得到正确的结果集。到现在为止还挺好。

现在我想做的是使用相同的命名查询来执行计数查询。我正在执行以下操作：

final Query q = em.createNamedQuery("query.all.absences.by.name");
q.setParameter("name","aRandomAbsenceName");
q.setHint(QueryHints.QUERY_TYPE, "org.eclipse.persistence.queries.ReportQuery");
final ReportQuery test = JpaHelper.getReportQuery(q);
test.addCount();
test.setShouldReturnWithoutReportQueryResult(true);

如果我的命名查询没有参数，这种方法可以正常工作。但是使用参数，如果我执行上面定义的 ReportQuery，我会遇到以下异常：

Exception [EclipseLink-6094] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.QueryException
Exception Description: The parameter name [name] in the query's selection criteria does not match any parameter name defined in the query.
Query: ReportQuery(referenceClass=AbsenceCategory sql="SELECT COUNT(CATEGORY_KEY) FROM ABSENCE_CATEGORY WHERE (CATEGORY_KEY = ?)")
    at org.eclipse.persistence.exceptions.QueryException.parameterNameMismatch(QueryException.java:1063)
    at org.eclipse.persistence.internal.expressions.ParameterExpression.getValue(ParameterExpression.java:275)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseCall.translate(DatabaseCall.java:1000)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:206)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:193)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelectCall(DatasourceCallQueryMechanism.java:264)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.selectAllRows(DatasourceCallQueryMechanism.java:646)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRowsFromTable(ExpressionQueryMechanism.java:2611)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllReportQueryRows(ExpressionQueryMechanism.java:2554)
    at org.eclipse.persistence.queries.ReportQuery.executeDatabaseQuery(ReportQuery.java:846)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:844)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1040)
    at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:392)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1128)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2871)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1516)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1498)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1449)

我还能如何将参数设置为 ReportQuery？

我正在使用 EclipseLink 2.0。

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1 回答 1

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你是如何执行 ReportQuery 的？您需要调用 Session.executeQuery(query, arguments) 并传递参数列表（顺序与 query.getArguments() 相同。

您可能还可以使用 JpaEntityManager createQuery(DatabaseQuery) API 将 ReportQuery 转换回 JPA 查询，然后您可以通过 JPA 方式设置参数。

于 2013-08-28T13:35:21.447 回答