Conditionally Generating Random Number

[rsmith]

All,
I'm writing a script that does the following, takes user sign-up information and stores it in a database, then e-mails the user a welcome e-mail with account summary information. This part works great.

 What I need to do is generate a random 10-digit number that will be assigned to each user at the time of sign-up. Generating the number is easy enough.

$number = rand(000000001, 9999999999);

 My problem is after the number is generated I need to query the database to see if the number is already assigned. Now I know the likelihood of a duplicate number being generated with the parameters I'm using is microscopic but I still have to make 100% certain that a duplicate number is not assigned. If by chance the number is already assigned I need it to go back and generate a new number before inserting it into the db with the rest of the data. What's the best way to go about this?

TIA

[m_tt]

Just loop it...

$unique_id = false;
while( $unique_id === false )
{
	$number = rand( 1, 9999999999 );

// Query database for duplicate $number

// If no duplicate is found set $unique_id = $number ( killing the loop )

// Otherwise, continue until $unique_id has no duplicate
}

[rsmith]

Thanks! I'll try this when I get home. The only thing is the number has to be no less than 10 digits, hence all the leading 0's if the first account is 0000000001.

Again, thanks for the help.

[m_tt]

Just use ZEROFILL in your database and it will add them automatically..

`unique_id` mediumint(10) UNSIGNED ZEROFILL NOT NULL default '0000000000'