[英]Hibernate; HQL; why does the delete query not work, but select does?
[英]Why does Hibernate HQL work, but Criteria does not?
我有一個簡單的模型,它只是一對多關系的鏈:國家-<城市-<街道表被映射為實體,並作為Map返回。
以下測試方法產生奇怪的結果:
public static void main(String[] args) {
Session session = HibernateSessionFactory.getSession();
List<Map<String, Object>> results = null;
//Query using HQL and print results
System.out.println("FROM HQL =====================");
String hql = "from Street where City.Country.countryid = 1";
Query query = session.createQuery(hql);
results = query.list();
for(Map<String, Object> row : results) {
System.out.println(row);
}
//Query using Criteria and print results
System.out.println("FROM CRITERIA ================");
Criteria criteria = session.createCriteria("Street");
criteria.add(Restrictions.eq("City.Country.countryid", 1));
results = criteria.list();
for(Map<String, Object> row : results) {
System.out.println(row);
}
}
使用HQL的最上面的塊按預期工作,但是最下面的塊掉落:
輸出:
FROM HQL =====================
{streetname=Mayfair, City=org.hibernate.proxy.map.MapProxy@2b12e7f7, $type$=Street, streetid=1}
{streetname=Park Lane, City=org.hibernate.proxy.map.MapProxy@2b12e7f7, $type$=Street, streetid=2}
{streetname=Bond Street, City=org.hibernate.proxy.map.MapProxy@663b1f38, $type$=Street, streetid=3}
{streetname=Old Kent Road, City=org.hibernate.proxy.map.MapProxy@663b1f38, $type$=Street, streetid=4}
FROM CRITERIA ================
Exception in thread "main" org.hibernate.QueryException: could not resolve property: City.Country.countryid of: Street
at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:67)
at org.hibernate.persister.entity.AbstractPropertyMapping.toColumns(AbstractPropertyMapping.java:82)
at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:54)
at org.hibernate.persister.entity.AbstractEntityPersister.toColumns(AbstractEntityPersister.java:1367)
at org.hibernate.loader.criteria.CriteriaQueryTranslator.getColumns(CriteriaQueryTranslator.java:457)
at org.hibernate.loader.criteria.CriteriaQueryTranslator.getColumnsUsingProjection(CriteriaQueryTranslator.java:417)
at org.hibernate.criterion.SimpleExpression.toSqlString(SimpleExpression.java:68)
at org.hibernate.loader.criteria.CriteriaQueryTranslator.getWhereCondition(CriteriaQueryTranslator.java:357)
at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:113)
at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:82)
at org.hibernate.loader.criteria.CriteriaLoader.<init>(CriteriaLoader.java:91)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1578)
at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:306)
at com.bar.foo(Main.java:33)
我看不到為什么HQL可以解析City.Country.countryid,但條件(限制)無法解析。
我是否缺少明顯的東西?
因為您為hql查詢使用了錯誤的語法。 幾個故障:
嘗試這個:
Criteria criteria = session.createCriteria(Street.class)
.createAlias("city", "ci")
.add(Restrictions.eq("ci.country", country))
有關更多詳細信息,請參見休眠參考 。
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