> I wonder: Is it worthwhile to use prepared statements in cases where
> multiple applications use essentially the same queries, but each application
> only once? For example, just about every application asks user for login and
> password and validates it against the database. Obviously the same query
> will be called many times (if there are many users), but probably only once
> per instance of the application.

Firebird doesn't cached statements issued by applications and moreover
doesn't share prepared statement between connections. But there is exceptions :
system queries, used by the engine to load\update metadata, stored procedures
and triggers. All this kind of statements are cached and shared between all
connections. So, if you really need to save time of parsing of some often executed
query(s) - use stored procedure for this purpose.

Regards,
Vlad