Hibernate/JPA + Derby-SELECT语句在GROUP BY，ORDER BY或选择列表中有太多项 [英] Hibernate/JPA + Derby - SELECT statement has too many items in GROUP BY, ORDER BY or select list

问题描述

我将Hibernate用于Derby DB的JPA DB映射.对于复杂的对象结构，我得到"org.apache.derby.client.am.SqlException:SELECT语句在GROUP BY，ORDER BY或选择列表中包含太多项":

I use Hibernate for JPA DB mapping with Derby DB. For a complex object structure I am getting "org.apache.derby.client.am.SqlException: SELECT statement has too many items in GROUP BY, ORDER BY or select list":

org.apache.derby.client.am.SqlException: SELECT statement has too many items in GROUP BY, ORDER BY or select list.
        org.apache.derby.client.am.Statement.completeSqlca(Unknown Source)
        org.apache.derby.client.net.NetStatementReply.parsePrepareError(Unknown Source)
        org.apache.derby.client.net.NetStatementReply.parsePRPSQLSTTreply(Unknown Source)
        org.apache.derby.client.net.NetStatementReply.readPrepareDescribeOutput(Unknown Source)
        org.apache.derby.client.net.StatementReply.readPrepareDescribeOutput(Unknown Source)
        org.apache.derby.client.net.NetStatement.readPrepareDescribeOutput_(Unknown Source)
        org.apache.derby.client.am.Statement.readPrepareDescribeOutput(Unknown Source)
        org.apache.derby.client.am.PreparedStatement.readPrepareDescribeInputOutput(Unknown Source)
        org.apache.derby.client.am.PreparedStatement.flowPrepareDescribeInputOutput(Unknown Source)
        org.apache.derby.client.am.PreparedStatement.prepare(Unknown Source)
        org.apache.derby.client.am.Connection.prepareStatementX(Unknown Source)
        org.apache.derby.client.am.Connection.prepareStatement(Unknown Source)
        org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:505)
        org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:423)
        org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:139)
        org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1547)
        org.hibernate.loader.Loader.doQuery(Loader.java:673)
        org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
        org.hibernate.loader.Loader.loadEntity(Loader.java:1860)
        org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:48)
        org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:42)
        org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3044)
        org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:395)
        org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:375)
        org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:139)
        org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:195)
        org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:103)
        org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:878)
        org.hibernate.impl.SessionImpl.get(SessionImpl.java:815)
        org.hibernate.event.def.DefaultMergeEventListener.entityIsDetached(DefaultMergeEventListener.java:229)
        org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:120)
        org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:53)
        org.hibernate.impl.SessionImpl.fireMerge(SessionImpl.java:677)
        org.hibernate.impl.SessionImpl.merge(SessionImpl.java:661)
        org.hibernate.impl.SessionImpl.merge(SessionImpl.java:665)
        org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:228)
        sun.reflect.GeneratedMethodAccessor376.invoke(Unknown Source)
        sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        java.lang.reflect.Method.invoke(Unknown Source)
        org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:365)
        $Proxy74.merge(Unknown Source)
        sun.reflect.GeneratedMethodAccessor376.invoke(Unknown Source)
        sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        java.lang.reflect.Method.invoke(Unknown Source)
        org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
        $Proxy41.merge(Unknown Source)

有人遇到过这个问题吗，如果解决方案是什么?我在想

Has anyone run into this problem and if what was the solution? I am thinking of

• 切换到MySQL
• 懒惰地加载一些属性(fetch = FetchType.LAZY)
• 重新设计数据库架构(现在可能很难，因为数据库是使用XSD架构中的Hyperjaxb生成的，因此必须更改shemas)

您会选择哪种解决方案?您知道Derby对于SQL语句的局限性吗?

For which solution would you go? Do you know what are the limitations of Derby for SQL statements?

推荐答案

我相信Derby在GROUP BY子句中允许大约32,000列.对于ORDER BY和SELECT列表中命名的列也有类似的限制.

I believe Derby allows approximately 32,000 columns in the GROUP BY clause. There are similar limits for ORDER BY, and for the columns named in the SELECT list.

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