Question

I am faced with very strange problem, and can’t find a way to resolve it. I wrote the following HQL in intellij’s HQL Console

update NewsEntity ne set ne.main=false where ne.main=true

StackTrace

java.lang.IllegalArgumentException: node to traverse cannot be null!
 at org.hibernate.hql.ast.util.NodeTraverser.traverseDepthFirst(NodeTraverser.java:31)
 at org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:254)
 at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:157)
 at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111)
 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)
 in RemoteSessionImpl.createQuery(RemoteSessionImpl.java:50)
 in RemoteUtil.executeWithClassLoader(RemoteUtil.java:122)
 in RemoteUtil$2$1.invoke(RemoteUtil.java:81)
 in HibernateEngine.createQuery(HibernateEngine.java:142) 

When I write a delete query I don’t have the same problem.

I have based this query around the following article HQL update query. But, can’t seem to figure out why I am still having this problem.

Answer 1

The idea of an ORM like Hibernate is to avoid such update queries.
You’ve just to load the object from the db, change the field and then Hibernate will update the object for out.

Query query = session.createQuery("from NewsEntity ne where ne.main = true");
NewsEntity newsEntity = (NewsEntity) query.uniqueResult();
newsEntity.setMain=false;
//Hibernate will update the object

If there’re more objects:

List<NewsEntity> newsEntities = (List<NewsEntity>) query.list();
for(NewsEntity entity : newsEntities)
{
 entity.setMain=false;
}

Hibernate also supports DML statements, so to do an update query you should do:

Query query = session.createQuery("your update query");
int result = query.executeUpdate();