The GSA works by crawling a start url on your site which you set up in the GSA and it will then follow any links from the start url throughout your site.
If you have any data in the DB you wish to search such as events or recipes you can create a page which pulls all events from the DB and lists them. Add this page to GSA so that it knows to crawl it and also make sure to exclude it in the frontend you set up in GSA.
In the enterprise version of the GSA you can also use SQL queries.
The GSA can crawl static pages and dynamic pages so it doesnt really matter what DB your cms uses.