Hypothetical question...

If I use the rand() function to generate user_ids what are the chances that I will get a duplicate ID for someone who is registering for the first time?

If it is likely that the rand() function will spit out the same number more than once is it wise to do a check to see if the ID is already in the db? maybe a dumb q.

Also, is it possible to generate a number or ID in a certain format suck as "3498-484DjL"?
I think that would be better than regular numbers....

thanks for any insight on this.
later.

Why the need for the complicated IDs?

Why not just have the field as a number then set the field to auto increment then everytime you enter a record into that table in the database the id field will increase by one.. thats the general way everyone does it..

Also time() will never return the same value (unless two users wil register at the same moment).

yeah ok so how do you handle a user that is no longer active? Do you delete the user altogether or do you change a field in the table saying he is no longer active? If I delete him his user ID goes with him right? Then I will have a table with users with IDs that don't follow sequentially. I just don't know if that is going to pose a problem in the future...

I was doing it the auto increment way until I noticed that when I delete a ficticious user (still in production stages) and then test the register script again I see that the auto number skips whatever ID number was deleted. Since this is my first real web app I don't want any issues with the DB.

just worried in BK,NY.

well you can have the script check the db to see if the ID is already in use, if it is you can just loop the script untill the ID isn't in use.

Chris