Hi.
I'm trying to execute a Criteria query which filters the root entity using fields contained in it's many-to-one associated objects. It should be easy to do but, I got strange errors.

My database looks like this:
Student table has FK that references Group table
Group Table has FK that references Teacher table.
Theese two associations are mapped as many-to-one in hibernate.

Now I try Criteria query like this:

Criteria crit = session.createCriteria(Student.class)
Criteria crit2 = crit.createCriteria("group") // 'group' is a property in Student class.
crit2.add(Expression.eq("teacher",t)); //'teacher' is a property in Group class, t is a Teacher object.

I got this exception:

org.hibernate.exception.SQLGrammarException: could not execute query
...
Caused by: java.sql.SQLException: Unknown column 'group1_.teacher_id' in 'where clause'

When I looked at the SQL query generated by hibernate it turned out, that the Group table wasn't in FROM clouse at all, but in WHERE clause was 'group1_.teacher_id=?'.

The above works well for one-to-many associations (ex. when I query Group class and make some conditions on fields in Student). How should it look for many-to-one? Is it posiible that the fact I use composite PK is messing up?

Oh, I forgot to add last statement. IT should be:

Criteria crit = session.createCriteria(Student.class)
Criteria crit2 = crit.createCriteria("group") // 'group' is a property in Student class.
crit2.add(Expression.eq("teacher",t)); //'teacher' is a property in Group class, t is a Teacher object.

List list = crit.list();

The last statement couses the exception.

try with:


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Thanks, but I tried that. I got this exception:

org.hibernate.QueryException: could not resolve property: group.teacher of: pl.teb.entities.Student

And no SQL query is generated.

Then try with:


Also, I think that in your first code you should have:


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I tried it and I got the exception:

org.hibernate.QueryException: could not resolve property: teacher of: Student

On list() operation. Any suggestions?

It looks like you are trying to query by Example, so I would suggest the following:



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