Question

how does the “tiny url” sites get so tiny ID url ?

i mean this : blabla.com/JH7

how can i get to such result? a functionality that is like md5 that does not repeat it self.
thanks in advance!

Answer 1

For example you can simply iterate trough string:

php > $str = 'aaa';
php > $str++;
php > echo $str;
aab

The another option is to prepare function which will generate random strings containing of a-zA-Z0-9 and than generate few millions of them into db (so you could just use them when needed) or do it in loop:

while( 1){
    $rand = randomString();
    if( isUnique( $rand)){
        break;
    }
}