Re: Basic question?What 's the key if there 's no FD(Functional Dependencies)?

From: paul c <toledobythesea_at_dbms.yuc>
Date: Sat, 04 Nov 2006 01:20:11 GMT
Message-ID: <fVR2h.247548$1T2.20753@pd7urf2no>

Aloha Kakuikanu wrote:
> NENASHI, Tegiri wrote:

>> Jan Hidders wrote:
>>> Do you know of any results that might be interesting for database
>>> theory and could not already be shown with good old set theory?
>> The categorical sketches to use for universal view updatability:
>>
>> Michael Johnson and Robert Rosebrugh.
>> Universal view updatability

>
> They claim to solve view updatability? OK, I have a table RealPeople
> with one attribute Name and the view
>
> CDTPosters =
> RealPeople
> union
> {(name=TeGiriNeNashi)}
>
> and a constraint
>
> RealPeople
> intersect
> {(name=TeGiriNeNashi)}
> =
> {}
>
> Is the CDTPosters view updatable?

I like that example, but can you come up with one that doesn't involve a constraint? (I think constraints muddy the waters and at worst confuse us with un-related questions.)

p Received on Fri Nov 03 2006 - 19:20:11 CST