Creating an online connection

I am creating a currency translation system and thought that i would create an online connection to the internet instead of using database. Is this possible, and how do i do it?

Or is creating database is already considered having an online connection?This means that the currency exchange rates are retrieved from the internet, and so when the convert button is clicked, the current values are converted to the currency exchange value.

And i thought of implementing ajax in my system, is this possible also?