This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
I just learned some basic knowledge about jsp&MySql, so I tried my best to do some practice. I designed a login system, and in my register_users table in database, there is one column which is String type, called ru_id, storing value to every register users, so the value in the column should be created automatically and can't not be the same in two of them.
So I want to know how randomly to get the only one String value, in restrict length, during registration in my this login system. Thank you.