Are discriminators allowed to be added in joined-subclasses ?

They are not allowed in joined-subclasses tag "only appears in subclass"..

I have joined subclasses and they are working fine; my problem is when i try to select objects of base class type I get the following exception

{"The maximum number of elements in the select list is 4096 and you have supplied 8942." }

That is because i have lots of objects inheriting from one base class and when nHibernate tries to join them in one select statement the columns count is so high as seen,

so,will the discriminator be helpful in that scenario ?
If so ,, How to use it ??
if not ,, How to tell nhibernate to select only the base class columns and the others after it figures out the type "that is why i wanted to use discriminator column"

thanks

Discriminators would be useless in <joined-subclass>.

In your case, you should probably avoid running queries on the base class... Do it directly on joined-subclasses.

Note that as <joined-subclass>es can be nested, you may divide the base class in many "second-level" base classes.

I do not need to select the base class , but the problem I need to add a field that is of type base class,,,

Is it possible to specify a field of base class type and values will be of a subset of the subclasses ? and tell hibernate to select only from these types tables ?