java Hibernate Critieria 将两个表与第 2 个表的条件连接起来并生成第一个表
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Hibernate Critieria join two tables with condition on 2nd table and result the 1st table
提问by changeme
I have a question using Hibernate Criteria, I need to convert this query using criteria.
我有一个使用 Hibernate Criteria 的问题，我需要使用标准来转换这个查询。
SELECT * FROM A a_ INNER JOIN B b_ ON a_.column1=b_.column1 AND b_.column2 IN (X,Y) AND active='Y';
SELECT * FROM A a_ INNER JOIN B b_ ON a_.column1=b_.column1 AND b_.column2 IN (X,Y) AND active='Y';
I need the result as table A.
我需要表 A 的结果。
采纳答案by Reddy
If the associations are defined, see http://docs.jboss.org/hibernate/core/3.3/reference/en/html/querycriteria.html#querycriteria-associations
In case associations are not specified in the entities definition, you can't use criteria. You can use HQL to do inner joins (need to write in implicit join notation), for doing left joins you have to use native SQL.
如果实体定义中未指定关联，则不能使用条件。您可以使用 HQL 进行内连接（需要用隐式连接表示法编写），为了进行左连接，您必须使用本机 SQL。
回答by Dennis Chen
I just solved this issue, here is my code
我刚刚解决了这个问题，这是我的代码
Criteria criteria = session.createCriteria(ProductOffer.class);
criteria.setResultTransformer(CriteriaSpecification.DISTINCT_ROOT_ENTITY);
Date effDate = TypeConvertUtil.toDate(param.get("effDate"));
criteria.add(Restrictions.le("effDate", effDate));
criteria.add(Restrictions.gt("expDate", effDate));
criteria.createAlias("productOfferPropDefs", "def",JoinType.LEFT_OUTER_JOIN);
criteria.setFetchMode("productOfferPropDefs", FetchMode.JOIN);
criteria.add(Restrictions.le("def.effDate", effDate));
criteria.add(Restrictions.gt("def.expDate", effDate));
criteria.createAlias("def.productOfferProps", "prop",JoinType.LEFT_OUTER_JOIN);
criteria.setFetchMode("def.productOfferProps", FetchMode.JOIN);
criteria.add(Restrictions.le("prop.effDate", effDate));
criteria.add(Restrictions.gt("prop.expDate", effDate));
productOfferList = criteria.list();
Please beware that
请注意
criteria.createAlias("productOfferPropDefs", "def",JoinType.LEFT_OUTER_JOIN);
this parameter is important:
这个参数很重要：
JoinType.LEFT_OUTER_JOIN
if you did not use it, and your relation is one-to-many, it will hit the 1:N classic issue for hibernate
如果您没有使用它，并且您的关系是一对多的，则会遇到休眠的 1:N 经典问题
