[pilot-db-list] two questions

[Albert R. <no_...@ir...>]

1. I wanna avoid to have repeated records with the same filed ID, so I 
would like to know if there's anyway to implement "principal keys or 
indexes" in DB.
The incremental ID solution don't solve my problem, I need especific IDs 
for every record.

2. I don't wanna seem a dumb, but I have terrible problems to do this 
whith a script:

(- %1 ( + %2 %3))
Explication:
First: field%2 + field%3 = result1
Then: field%1 - result1 = final result

I get an error message.

Thank you in advance.