I have the following situation :
I want to map a class to a view, but to insert rows into a table.
The view is a union of 2 tables with the same structure, but different primary keys, so a can't use the view to update one of the tables.
Any suggestion would be appreciated.
Thanks

I've done exactly that.

My solution is to name the view always: tableVIEW (so append the word view to the table name where you would like to insert/update/delete).
Then to create your own persister, which just delegates all the calls for save/update/delete to it's base class, but removes the word 'view'.

works like a charm, but it's not the most beautifull code perhaps.
If there are other insights, i'd love to hear them myself

I have found a lot of references about customer persister on this forum, but no example.
Could you post an example of your persister ?

If you are using SQL Server 2000 or higher, you can use a feature called INSTEAD OF TRIGGERS. These triggers allow to define the update/insert/delete behavior for a view that would otherwise be read-only. That way, you just have to map the view as you would if it were a table.

Thanks for your reply, but I want the application to be portable to another DB, so I rather not use MSSQL features.
An example of custom persister would be great.

I can't. I developed it for a customer.
But it's really a class of about 20 lines only...

Check the nhibernate source for examples on how to create your own persistor.