This might be a silly question I am building a site at the mo that has a mysql database that users can search and pull up info, my question is do google etc index databases.
For example if I have a site about dogs and all the info is in a database if someone searched for info on a particular type of dog would google ever pull up my info if I never hard coded a page about it.
Google will only ever follow links or, at best, select items from a list. It won't type text into search boxes. If you can access a page by following links then Google can. Anything that requires users to log in or to type text into an input field is outside its reach.
Search engine bots cannot perform actions such as searches, filling out forms, etc. So if all your info is in a database and it is not hard-coded into a page, and a search must be performed to find it; it will not get indexed. Bots need a URL structure to get around your site, so they'll crawl all the pages they have links to, and then leave. And if your content is hidden behind a wall (such as a search, login etc), there is no way for then to find it.