Transactions and db_debug

Hi,

i want to use transactions. For testing i executed a wrong query. Then the script aborts and i can't show a message or hint to the user. Can i disable db_debug for a specific controller or action? If not, how can i handle db errors correctly without db_debug setting to true? It helps a lot to see the error immediately on development (thats why i dont want to set it to false for the whole page), but in my case of transactions i don't want to exit the script.