Need best method to check if ID exists

[mikethecoder]

On part of a site I am working on, I need to generate a random code such as "HG877JHSA6S778DFF" for example. I will store the code in a field in the database. The problem is that when I need to create a new random code for when this event happens again, they can not be duplicated. What is the best way to do this? Obviously I could just generate the code, query the database and look for more than 1 result, if so then generate a new one and check that and repeat, or if it doesn't already exist commit it to the database. But this table may eventually grow very very large and I was wondering if generating a code and querying that one value against the whole table is really the most efficient way to do this. Any other better ways/setups out there? Thanks!

[pocobueno1388]

You may be able to use uniqid(). This generates a random code that is never the same twice.

[quiettech]

Or, since you are using it in a database anyways, you can use the built-in mysql function

 

mysql> INSERT INTO table_name VALUES( 'id', 'name', UUID() );