Re: is pivoted phones view updateable?

Aloha Kakuikanu a écrit :

> Tchuzhie Giri wrote:
> > It is not "OK" so long as one does not have your rules of updatability.
> > You put a pile of symbols on the pile of symbols: it does not have
> > sense without the rules. Please provide the rules, simple examples
> > and then one can go to more complex examples.
>
> Given two relation variables
>
> Y(n, #) -- aka WorkPhones(name, number)
> and
> Z(n, #) -- aka CellPhones(name, number)
>
> and two relation constants
>
> A = {(t='work')}
>
> and
>
> B = {(t='cell')}
>
> is the view
>
> X = (Y /\ A) \/ (Z /\ B) -- aka ConsolidatedPhones
>
> updateable? There is no minus operator involved. The only two RA
> operators are join /\ and union \/.

How exactly do you intersect Y and A AND Z and B with no FK? What unary relation is t? Received on Fri Nov 10 2006 - 13:17:02 CET