Hibernate version: 2.17


I have 2 classes: Task and Group (TASK and GROUP tables respectively). There is one-to-many association from Task to Group.

public class Task implements Serializable {
private taskId Integer;
...

public Integer getTaskId() {
return taskId;
}
private void setTaskId(Integer taskId) {
this.taskId = taskId;
}
...
}


public class Group implements Serializable {
private groupId Integer;
private Task task;
...

public Integer getGroupId() {
return groupId;
}
private void setGroupId(Integer groupId) {
this.groupId = groupId;
}
public Task getTask() {
return task;
}
public void setTask(Task task) {
this.task = task;
}
...
}

Everything is working ok (I mean all CRUD operations and stuff).

For a particular taskId I want to know how many Group(s) exist. The SQL would be :
SELECT count(*) FROM GROUP WHERE task_id = ?

Now I want it to do through Hibernate Query Language. So I wrote this code:

Integer taskId = ... // task Id to check
String hQuery = "select count(*) from Group g where g.task.getTaskId() = :taskid";
Query query = HibernateUtil.getSession().createQuery( hQuery );
query.setInteger( "taskid", taskId.intValue() );
Integer rows = (Integer)query.uniqueResult();

I got an error message :

2005-03-22 12:14:35,246 ERROR [STDERR] net.sf.hibernate.QueryException: could not resolve property: getTaskId of: com.trax.scheduler.model.Task [select count(*) from com.trax.scheduler.model.Group g where g.task.getTaskId() = :taskid]
at net.sf.hibernate.persister.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:38)
at net.sf.hibernate.hql.PathExpressionParser.getPropertyType(PathExpressionParser.java:249)
at net.sf.hibernate.hql.PathExpressionParser.end(PathExpressionParser.java:288)
at net.sf.hibernate.hql.WhereParser.doPathExpression(WhereParser.java:336)
at net.sf.hibernate.hql.WhereParser.doToken(WhereParser.java:366)
at net.sf.hibernate.hql.WhereParser.token(WhereParser.java:251)
at net.sf.hibernate.hql.ClauseParser.token(ClauseParser.java:87)
at net.sf.hibernate.hql.PreprocessingParser.token(PreprocessingParser.java:123)
at net.sf.hibernate.hql.ParserHelper.parse(ParserHelper.java:29)
at net.sf.hibernate.hql.QueryTranslator.compile(QueryTranslator.java:149)
at net.sf.hibernate.hql.QueryTranslator.compile(QueryTranslator.java:138)
at net.sf.hibernate.impl.SessionFactoryImpl.getQuery(SessionFactoryImpl.java:293)
at net.sf.hibernate.impl.SessionImpl.getQueries(SessionImpl.java:1561)
at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1532)
at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:39)
at net.sf.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:541)
...


Hibernate is wrongly assuming the getTaskId() method of Task class as a property.

Any suggestion?

Thanks

if i change the query to :

String hQuery = "select count(*) from Group g where g.task.taskId = :taskid";

it works. And Hibernate is smart enough to not load the task object first before executing the above query.
Looks like the methods are not supported in Hibernate query???

I had a similar issue and found the same thing that you did. The classes that I am using have composite keys, so I have methods within the classes that return a specific property from within the key. However, that won't work in HQL - I think we need to use direct properties only. So, for example if I have
classes QO, which has a primary key with properties j and q, and I want to refer to property q of the PK, even if I have a getQ() method, I have to say



Thanks for posting what you did. I'm trying to pull a group of records out of a set of 100K records, and the only way I can do it that I can see is by using HQL to grab just what I need from the database. I was stuck on the syntax for using the comp_id properties until I saw this thread.

Dave