Generating random numbers
in [Databases]
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From: "A. Joseph" on 16 Apr 2008 19:00 What is the best way to generating random numbers and you are sure that the script will never generate the generated ones? I`m using mysql database, but this out of SQL AUTO_INCREMENT stuff, I need a real random generator that will never generate what has been generated.
From: "TG" on 16 Apr 2008 20:05 Is the most important thing to be random or to be unique? If you need unique, you can use a timestamp including microseconds. Maybe using something like microtime(): http://us.php.net/manual/en/function.microtime.php The only other way you're probably going to guarentee that you don't repeat numbers is to keep a list of what's been used and compare against it. Otherwise, there's always going to be a slim chance you'll repeat a number. What do you plan on using it for? Maybe someone can give a better recommendation for what you need. And will this number be generated by PHP or the database? Or can it be either? -TG ----- Original Message ----- From: "A. Joseph" <joefazee(a)gmail.com> To: "Evert Lammerts" <evert.lammerts(a)gmail.com> Cc: "php-db(a)lists.php.net" <php-db(a)lists.php.net> Date: Thu, 17 Apr 2008 00:00:21 +0100 Subject: [PHP-DB] Generating random numbers > What is the best way to generating random numbers and you are sure that the > script will never generate the generated ones? > > I`m using mysql database, but this out of SQL AUTO_INCREMENT stuff, I need a > real random generator that will never generate what has been generated.
From: Chris on 16 Apr 2008 21:10 TG wrote: > Is the most important thing to be random or to be unique? If you need > unique, you can use a timestamp including microseconds. Maybe using > something like microtime(): > http://us.php.net/manual/en/function.microtime.php > > The only other way you're probably going to guarentee that you don't repeat > numbers is to keep a list of what's been used and compare against it. > Otherwise, there's always going to be a slim chance you'll repeat a number. > > What do you plan on using it for? Maybe someone can give a better > recommendation for what you need. And will this number be generated by > PHP or the database? Or can it be either? There's also http://au.php.net/uniqid - you could even use a different prefix for each call. -- Postgresql & php tutorials http://www.designmagick.com/
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