Yes i tried this and if(exists and i cannot get it to work like this for some reason, i think i would be better off to just add filename, md5hash, and any other value to a hash.
My only question then would be, if i printed the filename and md5, would the md5 match the filename?
ive never used hashes but was told they are great as long as your not worried about the order of the elements in them. all i can do is code it and try :)