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thinkpad
 Post subject: Restrictions.ne() on a list of attributes
PostPosted: Tue Apr 29, 2008 7:13 am 
Beginner
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Joined: Fri Apr 11, 2008 1:48 am
Posts: 36
Hello world,

I got an problem:

I have got a Bean (for example: Person) which gots an one-to-many relation to another bean (for example: clothes). So I got within my bean person a list of clothes.

I do want to create an criterion, which has a restriction: Restrictions.ne("clothes.name", "shirt")

I want to get a list of persons, who does not have a shirt in their clothes list.

The result seems to be wrong: I don't get persons who have only shirts in their clothes list. If they have other clothes and shirts, they will be shown in the result list.
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FlukeFan
 Post subject: Restrictions.ne() on a list of attributes
PostPosted: Fri May 02, 2008 5:53 am 
Senior
Senior

Joined: Thu Jun 21, 2007 8:03 am
Posts: 127
Location: UK
Hi,

I think you need to use a correlated subquery to get the results you're after. In NHibernate it would be:

Code:
DetachedCriteria shirts =
    DetachedCriteria.For(typeof(Person), "SubPerson")
        .Add(Expression.EqProperty("SubPerson.id", "Person.id"))
        .CreateAlias("Clothes", "Clothes")
        .Add(Expression.Eq("Clothes.Name", "Shirt"))
        .SetProjection(Projections.Property("Clothes.Name"));

IList<P> peopleWithoutShirts =
    session
        .CreateCriteria(typeof(Person), "Person")
        .Add(Subqueries.NotExists(shirts))
        .List<P>();


I'm not sure what the Hibernate equivalent is, but it will be pretty close to this.

Regards,
Richard
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thinkpad
 Post subject:
PostPosted: Sat May 03, 2008 12:22 pm 
Beginner
Beginner

Joined: Fri Apr 11, 2008 1:48 am
Posts: 36
Thank you very much. I did post this thread in the wrong section. Your solution seems to be working, but I get an error message. See here:

http://forum.hibernate.org/viewtopic.ph ... 62#2384262
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FlukeFan
 Post subject: Restrictions.ne() on a list of attributes
PostPosted: Sat May 03, 2008 1:31 pm 
Senior
Senior

Joined: Thu Jun 21, 2007 8:03 am
Posts: 127
Location: UK
Hi,

I think the reason you're getting an error is that you need to alias the main query and the sub-query with different aliases, then correlate them.

So, the main criteria needs an alias ('Person' in my example), and the detached criteria has a different alias ('SubPerson' in my example), and the detached criteria needs to join on these, so the key part of the query is:

Code:
.Add(Expression.EqProperty("SubPerson.id", "Person.id"))


Hope that helps.

Regards,
Richard
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thinkpad
 Post subject: Re: Restrictions.ne() on a list of attributes
PostPosted: Sat May 03, 2008 2:06 pm 
Beginner
Beginner

Joined: Fri Apr 11, 2008 1:48 am
Posts: 36
FlukeFan wrote:
Hi,

I think the reason you're getting an error is that you need to alias the main query and the sub-query with different aliases, then correlate them.

So, the main criteria needs an alias ('Person' in my example), and the detached criteria has a different alias ('SubPerson' in my example), and the detached criteria needs to join on these, so the key part of the query is:

Code:
.Add(Expression.EqProperty("SubPerson.id", "Person.id"))


Hope that helps.

Regards,
Richard


This does not work. My DetachedCriteria does not know the alias of the criteria. Or do I have to create an alias for the detached critiera in my main criteria?

Tried this:
Code:
Criteria crit = _session.createCriteria(Person.class, "con");
      
      DetachedCriteria buy =
          DetachedCriteria.forClass(Person.class, "dc")
             .add(Restrictions.eq("dc.id", "con.id"))
              .createAlias("clothes", "bi")
              .add(Restrictions.eq("bi.name", "shirt"))
              .setProjection(Projections.id());

      crit.add(Subqueries.notExists(buy));


Thank you very much...
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FlukeFan
 Post subject: Re: Restrictions.ne() on a list of attributes
PostPosted: Sat May 03, 2008 2:59 pm 
Senior
Senior

Joined: Thu Jun 21, 2007 8:03 am
Posts: 127
Location: UK
Hi,

Yes, that looks correct (or at least it looks the same as mine). If that still doesn't work, you could try posting the whole exception + mapping (either here, or in the other thread).

Regards,
Richard
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thinkpad
 Post subject:
PostPosted: Mon May 05, 2008 4:25 am 
Beginner
Beginner

Joined: Fri Apr 11, 2008 1:48 am
Posts: 36
Hi FlukeFan,

please have a look at this thread:
http://forum.hibernate.org/viewtopic.ph ... 54#2384354

Problem solved, but still far away from my target :-(
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