It does sound like either you haven’t created a database through the control panel yet, or you haven’t configured your code correctly to use it.
When establishing the MySQL connection, you should be able to specify the name of the database to connect to (not to be confused with the database hostname). Please make sure you’re doing that in your code.
Also, I’m not sure if your use of promo/trn_logs is valid. AFAIK the slash character is not a valid character for table names. This may cause the connection to select the wrong database. Can you please double check the database table too?