How does a search engine find a dynamic URL address that's based on values in a DB?

[eluser]Dandy_andy[/eluser]
That particular page, www.domain.com/members/45 would exist if you were to type it in to the browser, but doesn't exist as a static page that can be crawled. So based on this, if I would like to have all the member details accessible by all the search engine robots (for example each page is unique in some way), then I would need to have a link to it or generate a static page of some sort? I presume this is why my current system (I didn't design the website by the way) creates an index.php file in a publically accessible folder so that when accessed, it runs the relevant function and generates the page. Are there any other ways to do this?