Question

I need to work out a way to create 10,000 non-repeating random numbers in PHP, and then put it into database table. Number will be 12 digits long.

What is the best way to do this?

Answer 1

This assumes that you can generate a 12 digit random number without problems (use getrandmax() to see how big you can get….according to php.net on some systems 32k is as large a number as you can get.

$array = array();

while(sizeof($array)<=10000){
  $number = mt_rand(0,999999999999);
  if(!array_key_exists($number,$array)){
     $array[$number] = null;
  }
}

foreach($array as $key=>$val){
  //write array records to db.
}

You could use either rand() or mt_rand(). mt_rand() is supposed to be faster however.