Are you going to use relational database to store this data? Or you goint to use image saving / object-oriented DB for persistence? iâd like to use voyage.. so i can use MongoDB for persistence.. 1) Are there strong asymmetry in queries? Which kind of queries are more frequent: "give me tags of this radio" or "give me radios with this tag"? i would say that at the end of the day, it is going to be about the same.. lots and lots of each call.. 2) Do you need to store other information EXCEPT fact that that radio is marked by this tag? For example, do you need to store the time tag was assigned to the station or the user who have assigned it? You got the idea, I believe. i am going to guess that there will be more information on this.. as in.. who created the tag.. so i can import JUST that userâs tags for their list.. while maintaining a set of tags as default tags.. 3) Are queries simple "stations with tag X" / "tags of station X", or they may often looks like "stations with tag A or B, but not both" or something even more complicated. queries will simply be.. give me all stations with this tag..  or these tags.. thanks! ---- peace, sergio photographer, journalist, visionary Public Key: http://bit.ly/29z9fG0 #BitMessage BM-NBaswViL21xqgg9STRJjaJaUoyiNe2dV http://www.Village-Buzz.com http://www.ThoseOptimizeGuys.com http://www.coffee-black.com http://www.painlessfrugality.com http://www.twitter.com/sergio_101 http://www.facebook.com/sergio101