[eluser]derekt[/eluser]
theprodigy - great point - I should put links to the galleries that each photo is in, which would help users find collections of photos they're after. As for putting the category id in a session, I could, but intuition tells me that I should try and minimize use of db and server resources for the sake of best performance, no?
jedd - I've set up dbs for photos, collections, and collection groups, with map tables defining which photo goes in which collection id, then which collection goes in which collection group. Single photos can be in many collections, and single collections can be in many collection groups. Also, thanks for the link, though I wasn't able to access the URL (server unexpectedly dropped the connection).
The Codeigniter/MVC way seems to suggest I pass collection group, category and photo in the URL like so:
site.com/travel-photos/fiji/clownfish
site.com/stock-photos/fish/clownfish
The results is many many URLs, which is fine, except that:
a) I'd like to provide others (especially search engines) with a single URL
b) I use CI's caching, so the result is a large number of cached files
I looked at how WordPress does this for news posts, and they use a single URL for an item's "permalink" (posts/news-headlines/post-name), then set a global which contains "category" and then make the category available via an "is_category" function so one can build the breadcrumb and next/prev links.
I can do whatever, but would love to have the advice of those who know much better than this photographer =)