On 26/08/15 03:40, Melvin Davidson wrote:
[...]
> IOW: If we have an account table, then the account_id or account_no
> would be the primary key. There is no need to have a separate
> serial id as the primary key.
[...]
Account numbers are externally generated, and may potentially change.
Management might suddenly decide that they want to start using the year
the account started as the first 4 digits, or that the branch code
should be reflected in it, or something else. The database should be
protected from these arbitrary changes. Hence the account_no is not a
good candidate for a primary key.
Cheers,
Gavin