I have a categories table of which is structured like so:
category_id INT [primary key]
access_url VARCHAR [index key]
When sorting the records via my application (of which will be used in a high traffic environment) does it make any difference whether a record is selected via it's index key vs the primary key? Is there any significant speed/memory differences from accessing records via a VARCHAR index key as opposed to an INT primary key?
The reason I ask this is because I want to use descriptive urls, using the 'access_url' field. ie. instead of http://www.mysite.com/category/2 (category_id) - I would have http://www.mysite.com/category-name (access_url)
I'd appreciate any help.
