Lots of databases out there but I don't know of one that is organized by traffic beyond the top 30 or so. Wikipedia has some lists of top 50 or 100 by continent or region and you can sort those by code.
http://en.wikipedia.org/wiki/Busiest...nger_boardings
http://en.wikipedia.org/wiki/List_of...orts_in_Europe

http://en.wikipedia.org/wiki/List_of_airports
http://www.iata.org/ps/publications/Pages/ccd.aspx
http://www.avcodes.co.uk/aptcodesearch.asp
http://www.nationsonline.org/oneworld/airport_code.htm