There are several different ways to go about this.
It basically rely's on how you have your system set
up.
For instance, if I have a product database, I do not
store each URL in the database, i generate that URL
"on the fly" based on certain criteria.
However If i were putting together a USER database
I would include a field for URL because that information
would always be different.
If you are setting up the webspace for these users, and
they are lets say under http://www.yoursites.com/~username
then you wouldnt have to store the absolute path to your
users webspace, you would just tack on ~username to the
end of your URL for each place you would like to put a LINK.
So, hopefully you understtood what I said, im really tired, and
was up very late last night watching the MATRIX!
Cheers.