if I use session in a web app
can I be assured that every guest who visits the site has a unique session id?
and for example I use a rand() to generate and store a $_SESSION
can I be assured that every set of rand() is also unique?
say min is 123456789 and max is 1234567890
how can I check each of sessions stored to see whether rand() has already generated same number?
is there such thing as looping through sessions?