I've used where clauses previously in the mapping layer to prevent certain records from ever getting into my application at the lowest level possible. (Mainly to prevent having to re-write lots of lines of code to filter out the unwanted records)

These have been simple, one column queries, like so

this.Where("Invisible = 0");

However a scenario has appeared which requires the use of an exists sql query.

exists (select ep_.Id from [Warehouse].[dbo].EventPart ep_ where Id = ep_.EventId and ep_.DataType = 4

In the above case I would usually reference the parent table Event with a short name, i.e. event_.Id however as Nhibernate generates these short names dynamically it's impossible to know what it's going to be.

So instead I tried using just Id, from above ep_ where Id = ep_.EventId

When the code is run, because of the dynamic short names the EventPart table short name ep_ is has another short name prefixed to it, event0_.ep_ where event0_ refers to the parent table.

This causes an SQL error because of the . in between event0_ and ep_

So in my EventMap I have the following

this.Where("(exists (select ep_.Id from [isnapshot.Warehouse].[dbo].EventPart ep_ where Id = ep_.EventId and ep_.DataType = 4)");

but when it's generated it creates this

select cast(count(*) as INT) as col_0_0_
from [isnapshot.Warehouse].[dbo].Event event0_
where (exists (select ep_.Id from [isnapshot.Warehouse].[dbo].EventPart event0_.ep_ where event0_.Id = ep_.EventId and ep_.DataType = 4)

It has correctly added the event0_ to the Id

Was the mapping layer where clause built to handle this and if so where am I going wrong?