Ben answered your question. You asked if one CAN use DW to call data. Just understand that it isn't necessary to use DW for this, and there are good reasons not to.
Using a plug-in or data behaviors allows you to get up and running quickly, but they are like training wheels on a bicycle. Eventually they cripple your capabilities and you have to go back to the beginning to learn how to do things right, which means making the connections and writing the code yourself. Why not just do it the right way from the start?
If you script the database connections and queries yourself, you can still work within DW.
You did not specify which kind of server, database or scripting language you plan to use. The typical configuration is MySQL database and PHP scripting on Linux.