Why do we use Meaningful PK or Meaningless PK ?

Hi All,

My questions below is very basic (I am a developer not a dba ..)

I see on database design that the Primary Key (PK) is usually not the "Key" that is visible to user, e.g : if we has Invoice table, the columns are :

InvoiceID (PK) => this is only visible to developer, user never see it, usually
using sequence.
InvoiceNumber => this is visible on UI, reports etc ....
>From the design point of view, what is the reason of the above design ?

Thank you for your help,
xtanto Received on Tue Sep 05 2006 - 10:04:53 CDT