Re: is pivoted phones view updateable?

Aloha Kakuikanu wrote:
> 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 \/.

I do not have an idea -- you did not give the rules of your dialect to deduce if the updation is possible. But one can deduce of your oblique talk that you utilize the rules of C.J. Date for the update of the union. If it is true then the insert updatability depends of the value of 't'. C.J. Date critiques his rule for this dependency but does not see a good choice.

To mutilate the name of person, it is of the bad taste. Is it that you try to rival Sacha Cohen ?

--
Tegi

In the SQL the view is never updatable.