java-QueryDSL重复标识变量/相等语法错误,是否存在Set？
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了java-QueryDSL重复标识变量/相等语法错误,是否存在Set？，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含6892字，纯文字阅读大概需要10分钟。
内容图文
我有这里概述的JPA实体：
QueryDSL JPA syntax error with contains on Set?
现在,我尝试在单个查询中对Set标记设置多个限制：
Set<Tag> withTags = ...;
Set<Tag> withoutTags = ...;
q.where(license.tags.any().in(withTags));
q.where(license.tags.any().in(withoutTags).not());
执行查询时,出现以下异常：
Exception [EclipseLink-8019] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Error compiling the query [select distinct license
from License license
where exists (select license_tags
from Tag license_tags
where license_tags member of license.tags and license_tags = ?1)
and not exists (select license_tags
from Tag license_tags
where license_tags member of license.tags and license_tags = ?2)]
multiple declaration of identification variable [license_tags], previously declared as [Tag license_tags].
我试图将as(“ withTags”)插入查询中,但是我能做的位置是在any()之后,该AS将JPQL中的AS插入关于我要解决的复制问题的错误位置.我可以将其插入到标签之后,但随后得到SimpleExpression作为返回值,无法执行any().
还有其他想法如何防止标识变量的这种重复？
另外,上面给出的语句仅在给定Set withTags / withoutTags仅包含单个值的情况下起作用.如果存在多个值,则会引发以下异常：
Exception [EclipseLink-6075] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions.QueryException
Exception Description: Object comparisons can only use the equal() or notEqual() operators. Other comparisons must be done through query keys or direct attribute level comparisons.
Expression: [Relation operator IN Base my.package.Tag Parameter 1]
select distinct license
from License license
where exists (select license_tags
from Tag license_tags
where license_tags member of license.tags and license_tags in ?1)
at org.eclipse.persistence.exceptions.QueryException.invalidOperatorForObjectComparison(QueryException.java:614)
at org.eclipse.persistence.internal.expressions.RelationExpression.normalize(RelationExpression.java:393)
at org.eclipse.persistence.internal.expressions.CompoundExpression.normalize(CompoundExpression.java:226)
at org.eclipse.persistence.internal.expressions.CompoundExpression.normalize(CompoundExpression.java:218)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.normalize(SQLSelectStatement.java:1306)
at org.eclipse.persistence.internal.expressions.SubSelectExpression.normalizeSubSelect(SubSelectExpression.java:134)
at org.eclipse.persistence.internal.expressions.ExpressionNormalizer.normalizeSubSelects(ExpressionNormalizer.java:93)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.normalize(SQLSelectStatement.java:1379)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.buildNormalSelectStatement(ExpressionQueryMechanism.java:482)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.prepareSelectAllRows(ExpressionQueryMechanism.java:1553)
at org.eclipse.persistence.queries.ReadAllQuery.prepareSelectAllRows(ReadAllQuery.java:793)
at org.eclipse.persistence.queries.ReadAllQuery.prepare(ReadAllQuery.java:734)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:464)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.checkPrepare(ObjectLevelReadQuery.java:732)
at org.eclipse.persistence.queries.DatabaseQuery.prepareCall(DatabaseQuery.java:1577)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:240)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:173)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:125)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:109)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1326)
at sun.reflect.GeneratedMethodAccessor552.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.weld.util.reflection.SecureReflections$13.work(SecureReflections.java:304)
at org.jboss.weld.util.reflection.SecureReflectionAccess.run(SecureReflectionAccess.java:54)
at org.jboss.weld.util.reflection.SecureReflectionAccess.runAsInvocation(SecureReflectionAccess.java:163)
at org.jboss.weld.util.reflection.SecureReflections.invoke(SecureReflections.java:298)
at org.jboss.weld.bean.proxy.ClientProxyMethodHandler.invoke(ClientProxyMethodHandler.java:113)
at org.jboss.weld.util.CleanableMethodHandler.invoke(CleanableMethodHandler.java:43)
at javax.persistence.EntityManager_$$_javassist_131.createQuery(EntityManager_$$_javassist_131.java)
at com.mysema.query.jpa.impl.DefaultSessionHolder.createQuery(DefaultSessionHolder.java:35)
at com.mysema.query.jpa.impl.AbstractJPAQuery.createQuery(AbstractJPAQuery.java:139)
at com.mysema.query.jpa.impl.AbstractJPAQuery.createQuery(AbstractJPAQuery.java:108)
at com.mysema.query.jpa.impl.AbstractJPAQuery.list(AbstractJPAQuery.java:276)
并使用EclipseLink 2.4
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: The SQL datatype to be used for an instance of mypackage.Tag cannot be determined. Use 'setObject()' with an explizit type, to define it.
Error Code: 0
Call: SELECT DISTINCT t0.ID, ...all the other properties...
FROM LICENSE t0, WHERE ((NOT EXISTS (SELECT ? FROM LicenseTags t5, TAG t4, TAG t3 WHERE (((t3.ID = t4.ID) AND (t3.ID IN (?,?))) AND ((t5.License_ID = t0.ID) AND (t4.ID = t5.tags_ID))))))
现在,我尝试使用以下QueryDSL语法解决此问题：
for (Tag tag : withTags) {
q.where(license.tags.contains(tag));
}
for (Tag tag : withoutTags) {
q.where(license.tags.contains(tag).not());
}
前一部分的确起到了吸引人的作用,但后者没有返回预期的结果.没有标签中包含标签的许可证不会像应有的那样从结果集中排除.
后者的JPQL和SQL如下所示：
select distinct license
from License license
where not ?1 member of license.tags
SELECT DISTINCT t1.ID, ...all the other properties...
FROM LicenseTags t2, LICENSE t1, TAG t0
WHERE (NOT (133170 = t0.ID) AND (t2.License_ID = t1.ID) AND (t0.ID = t2.tags_ID))
JPQL对我来说看起来不错,但如果许可证具有多个关联的标签,则SQL显然会失败.因此,我认为这实际上是EclipseLink的翻译失败的情况.我将看看这是否是我使用的版本的已知错误.该论文在某种程度上受到了JPQL “NOT MEMBER OF” query using criteria API的支持,尽管在那种情况下,仅在使用creteria api而不是JPQL时才出现问题.这种错误翻译仍然存在于EclipseLink 2.4 RC 2中.这是一种最终的解决方法,可以完成“无标签”部分的工作：
Collection<Integer> tagIds = new ArrayList<Integer>();
for (Tag tag : withoutTags) {
tagIds.add(tag.getId());
}
q.where(license.tags.any().id.in(tagIds).not());
此致蒂尔曼
解决方法:
您可以使用联接而不是子选择吗？这也将更加有效.
您也可以尝试EclipseLink 2.4,它可能没有这些问题.
QueryDSL支持innerJoin()和leftJoin()联接,您应该改用它.
内容总结
以上是互联网集市为您收集整理的java-QueryDSL重复标识变量/相等语法错误,是否存在Set？全部内容，希望文章能够帮你解决java-QueryDSL重复标识变量/相等语法错误,是否存在Set？所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。
来源：【匿名】