[Dovecot] SQL insert?

Hi,

I want to log some informations about a mail in a mysql database when the mail is saved to inbox (for a groupware). I use Dovecot 1.2.16 and the log message "msgid=<xxx>: saved mail to inbox" is generated in deliver.c. I find all the needed data in that file. But I'am not sure how to use the functions in sql-api.h or sql-api-private.h to send a simple SQL insert statement to the database. Can anyone give me a hint how to do this?

best regards, Oliver