Dear NHibernate users,

when we want to get a collection, we can use the elements keyword in our hql, but what if we want to get the Ids of the collection objects, ex:

string hql="SELECT elements(myCollection) from Category where ..."; works fine, we get all the Collection objects .
but what if i want to get only the ids of this Collection in my hql, cause i don;t need the other properties of the collection, i only need to access the id property for each object of the collection ...

Regards,
JojoRico

You could try:

It worked !!!
but Do you know (in this hql) if the collection attributes are all loaded and then there is a filtration in order to get the Id property, or is the Id property directly loaded from the db instead of loading all the properties than filtering the id?

Thanks a lot :)

look at the SQL generated to take the values.

I made a test myself and the select was something like this:



but if you want to be sure, watch out your log, or use the nqa application to test and see your HQL.

If you don't know nqa, i really like it:
http://www.ayende.com/projects/nhibernate-query-analyzer/downloads.aspx

Dear anuarneto,

thanks a lot
I've already asked about some hql analyser but nobody have replied ..

Regards,
Jojo