Some of the Zenphoto plugins I have created require additional database tables to be added to the existing Zenphoto DB, or add additional columns to existing tables.
I'm fine with the SQL code itself to create the tables / columns, as well as the checks that ensure they are not created if they already exist.
My problem - is there an 'install' callback so that a Zenphoto plugin can only complete the above tasks on installation, instead of on every page load?