Loop until returned true with PHP

Question

I'm generating a random code, and I need to check to be sure that the code isn't already in the database. I'm assuming this requires some type of a loop. I have my query all setup and I need it to run a block of code again if mysql_num_rows == 0.

Answer 1

$key = true;

    while($key){
        // Do stuff
        if(mysql_num_rows($result) > 0) $key = false;
    }