如何解决Spring JPA @Query如何连接子表和父表?
Class Entry {
int id;
String name;
}
Class NewEquipment extends Entry{
int id;
String name;
String type;
}
Class Inventory extends Entry{
int id;
String name;
String location;
}
db中有三个类和相关表,现在我需要一个查询:
@Query(value = "SELECT ne FROM Entry e INNER JOIN NewEquipment ne WHERE e.id = ne.id")
它引发如下异常,我不知道如何使用JPA加入子类和父类,我将不胜感激。谢谢!
Caused by: java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode
\-[IDENT] IdentNode: 'ne' {originalText=ne}
at org.hibernate.hql.internal.ast.tree.SelectClause.initializeExplicitSelectClause(SelectClause.java:174)
at org.hibernate.hql.internal.ast.HqlSqlWalker.useSelectClause(HqlSqlWalker.java:937)
at org.hibernate.hql.internal.ast.HqlSqlWalker.processQuery(HqlSqlWalker.java:705)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:665)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301)
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:249)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:278)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:206)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:158)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:131)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:93)
at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:167)
at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:301)
at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:236)
at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1836)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:328)
at sun.reflect.GeneratedMethodAccessor71.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at
解决方法
对此任务使用@Query有什么意义?您只需要定义适当的数据模型,spring / hibernate就会为您做联接表。那是简单的示例-https://tenmilesquare.com/spring-boot-jpa-relationship-quick-guide/
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