>Good function
>
>Do you think its really random, or based o system time or something like this ?

They are, I believe, time based. Successive calls yield results where the results are in sequence.

For better or worse, many of our tables were set up using SYS(2015) to generate uniq keys. I have not come across a problem with a duplicate entry in the two years I've been supporting it. This includes using statements such as

REPLACE ALL uniq_key WITH SYS(2015)

on cursors with over 5000 records.