...and depending on the licensing agreements, it can mean both things at the same time. The subscription agreements with the database suppliers and the policy of your library determines what you can do or not do.

For all libraries I know of, if you have a card already, your account number on the card is your access code. It's less complicated that way. If you haven't used your account in a while, you might want to check to make sure it's still active. Ours expire every three years, whether we use them or not, because we have colleges nearby. Students usually get cards, but they also forget to cancel them ("cancel library card" being #11 on their Top Ten list of "Things To Remember When I Graduate"). Automatic expiration helps us clean up our member database.

I can access ProQuest anywhere, anytime, provided I have my library card number. Not even the card, just the number. I store it in a secure online account, so I can copy and paste it into the little sign-in box, just in case I haven't got my keys with me. (Mine is a keychain card.) I could be in orbit around the Earth, and as long as I have an internet connection, I could access ProQuest, and almost all the other databases provided through the library. Any cardholder in our library system has 24/7 worldwide access, barring any maintenance outages by the library system or the database suppliers.

Two of the business databases to which we provide access insist they be tied to the IP addresses of individual PCs whose physical location is inside the library building. It's a licensing thing. If they said we were allowed to put them out on the Net, we would.

We also have access to Lexis-Nexis, but that's also on-site, and only for staff PCs. Just as well: they charge by the search, and so are not appropriate for noodling around. They are the Database of Last Resort for us, but for institutions with money, Lexis-Nexis is the first place to go, because it's that good.

We also have hot-linked shortcuts on the desktops of all library computers for all the databases that are free to the public, for people without cards, like travellers, or people who owe a gajillion dollars in replacement costs. (We don't usually keep people offline for fines, but non-returned items are another story.) They have access, but only in the library building itself. People who travel on business, especially people in sales, love this service. They drop in in the evenings, after their appointments for the day are done, and read their local paper. They also use the business databases to research the companies in the area that might buy from them.

Public libraries don't have any nationally uniform databases to which people have access no matter where they live. We're all pretty much local outfits, though for some, "local" covers a larger area than for others. Some are supplied by the state. You'll need to ask locally what's available. It really should be free, in the sense that your community, of which you are a member, picks up the user fees for everyone.