create a unique tracking code [duplicate]

This question already has开发者_运维知识库 answers here: Closed 11 years ago.

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how is create a unique tracking code

With this function i can create a unique tracking code?

What is your suggestion?

<?php echo strtotime("now");?>

The number of characters not more than 10. Please call example powerful

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What about the uniqid() function ?

Gets a prefixed unique identifier based on the current time in microseconds.

With this functions, chances are far better for you to get a unique code than just using a data like you did in your question.

Also, you might want to take a look at what a GUID is.

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It depends on the purpose of the your website...

In general, I would also add the user IP. so if two people are buying at the same time, you won't have an overlap.

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If two users visit at exactly the same time, then they would have the same tracking code. I recommend using the Unix epoch as a seed for the mt_rand() function.

//mt_srand(time()); Don't seed mt_rand
echo mt_rand();

You could also use it (or only a section of it, say the milliseconds) as a prefix or suffix to the random number. But that would pretty much emulate what uniquid() does.

Apparently seeding is bad and boring (see @Gumbo). So don't do it.