Re: "Armstrong's axioms" augmentation - help plz

Dan wrote:
>
> Ok. I see your point, but just make sure its crystal clear: the
> first three rules form the basis for the rest of the rules (including
> the alternative for augmentation that the OP stated).

Yes, all the other rules can be derived from these first three rules.

> Altering the augmentation rule in the form the OP presented would
> undercut a degree of completeness (as the basis for all remaining
> inferences are altered).

Exactly. Although "a degree of completeness" sounds a bit vague. The three rules are really complete, not just to a certain degree.

> I understand where you are coming from. Someone should probably
> notify Elmasri and Navathe that their wording could be misleading.

Ow, they really say this? I'll have to check my copy at work.

> Thanks for taking the time to explain.

You're very welcome. It's always a pleasure to talk to you.

• Jan Hiddesr