I just want to select a list of strings, or int32s, or other primitive types without any mapping. Is it possible, and how? Thanks.

you can get the ADO.NET connection object from the session which can be used to execute any SQL query you want .

cheers,
radu

You can use collection of values in NHib. For e,g a Set of strings can be declared as follows:

<set name="GroupNames" table="Names">
<Key column="GroupID"/>
<element column="Name" type="string"/>
</set>

Please see NHib documentation for more details