Random Number, if duplicate?

[Red Blaze]

<?php
srand ((double) microtime( )*1000000);
$random_number = rand( );
echo "$random_number";
?>

I want to use this random code generator, to store in the database a code. I want this number to be unique. How can I keep PHP from duplicating a code saved in the database?

I can tell MySQL to keep it unique, but I don't want an error page. I want to keep errors to a minimum. Thank you for the help.

I was thinking of a loop to check if it exists until it finds a unique number and end the loop before it spits out the page with the code in a hidden field. I just don't know what codes to use. >_<

[Marco van Herwaarden]

What are you trying to do with this?

[Red Blaze]

Well, I want this for a gallery. When someone makes an album, the random number generator would create a number. The user would have to keep this to go back to view the album. Kind of like a passcode... key kinda thing.

Why not just use mysql's auto_increment attribute, which adds a unique identifer to table rows?

[Red Blaze]

Well, I don't want single digit keys. Otherwise, random people will just type 1, 2, 3, 4, 5...and have access where they're not suppose to be.

[Marco van Herwaarden]

So you want to make it that anybody that want to view an album needs a password? Or just the original owner of the album when they want to edit it?

[Red Blaze]

If the users types in the correct passcode, they can view the album.

[Marco van Herwaarden]

And how will they get that password?

Wouldn't it be easiest if you let the user who creates the album just let choose a password?

[Red Blaze]

It would be emailed to them.
lol I have it figured out. I just want to know how to keep it from duplicating; if it ever happend.

[Paul M]

Why does it matter if you happen to get a duplicate ?