> anyone?
>
> how to monitor triggers into a database? any tools ?

If you want to a tool which generates triggers to keep track of data
changes, then have a look on IB LogManager:
http://www.upscene.com/products.audit.iblm_main.php

If you want to monitor execution of your own triggers, then FB
TraceManager via the Trace API might be an option:
http://www.upscene.com/products.fbtm.index.php

If you want to have user-defined logging in your trigger, then follow
Alexey's approach. With Firebird 2.5 you even don't need to do that with
external tables, but with a regular table (which is easier
queried/processed afterwards) in combination with the 2.5 autonomous
transactions, encapsulating the insert into log table into its own
dedicated (sub) transaction context.


--
With regards,
Thomas Steinmaurer
http://www.upscene.com/

Professional Tools and Services for Firebird
FB TraceManager, IB LogManager, Database Health Check, Tuning etc.