我无法在休眠hql查询中的两个表之间建立内部联接 [英] I can't make a inner join between two tables in hibernate hql query

问题描述

我对此很陌生.请帮助我.

I am new with this. Please help me.

我的内部联接看起来像这样: select p.idprodus, p.denumire, p.cantitate from Produs p inner join Furnizor f on p.idfurn = f.idfurn

My inner join looks like this: select p.idprodus, p.denumire, p.cantitate from Produs p inner join Furnizor f on p.idfurn = f.idfurn

我想在idfurn列上进行内部联接，但是出现以下错误:

I want to make the inner join on the column idfurn, but I get these errors:

org.hibernate.QueryException:必须在外部联接或完全联接之后加上路径表达式select p.idprodus, p.denumire, p.cantitate from sakila.entity.Produs p inner join Furnizor f on p.idfurn = f.idfurn

org.hibernate.QueryException: outer or full join must be followed by path expression select p.idprodus, p.denumire, p.cantitate from sakila.entity.Produs p inner join Furnizor f on p.idfurn = f.idfurn

at org.hibernate.hql.classic.FromParser.token(FromParser.java:170)
at org.hibernate.hql.classic.ClauseParser.token(ClauseParser.java:86)
at org.hibernate.hql.classic.PreprocessingParser.token(PreprocessingParser.java:108)
at org.hibernate.hql.classic.ParserHelper.parse(ParserHelper.java:28)
at org.hibernate.hql.classic.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:216)
at org.hibernate.hql.classic.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:185)
at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:77)
at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:56)
at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72)
at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133)
at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112)
at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1623)

推荐答案

在HQL中，您使用实体，而不是表.并且实体通过关联(OneToOne，OneToMany等)链接在一起，可以在关联的实体之间进行联接.

In HQL, you use entities, not tables. And entities are linked together by associations (OneToOne, OneToMany, etc.) Joins can anly be done between associated entities.

例如，如果您在产品"和提供者"之间建立了ManyToOne关联，则HQL查询为:

For example, if you have a ManyToOne association between Product and Provider, the HQL query is:

select p from Product p inner join p.provider provider where ...

on子句是不必要的，因为Hibernate从ManyToOne关联的映射中知道使用product.id_provider外键到provider.id_provider主键的产品与其提供者相关联.

The on clause is unnecessary, because Hibernate knows from the mapping of the ManyToOne association that a Product is associated with its provider using the product.id_provider foreign key to the provider.id_provider primary key.

在休眠文档.

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