ISN vs. KEY

, , ,
1

Hi All,

I know that ISN is unique.I want to know whether descriptor(key) unigue or is it must be non unigue? If it is a unique, then what is the difference between ISN and KEY?

Thanks,
Rohan.

2

Rohan,

ISN is guaranteed to be unique. However, with certain utilities, it can be re-assigned. It is not good to use as a key. Descriptors are built upon data in the file (like customer id number). These descriptors can be defined as unique or not (the default). There is a little overhead with the Unique Option, but it will guarantee that the value is unique within the file.

Richard Bryan
Database Administrator
Austin American-Statesman
ADABAS V813
NATURAL V423
PREDICT 452