Re: Nulls, integrity, the closed world assumption and events

>  > John Doe, has no cars.
>
> Non-MV person-table:
> Id(1) & Name(Tom) & Car(Nissan)
> Id(1) & Name(Tom) & Car(Porsche)
> Id(2) & Name(Bob) & Car(Aston Martin)
>
> MV person-table:
> Id(1) & Name(Tom) & Car(Nissan) & Car(Porsche)
> Id(2) & Name(Bob) & Car(Aston Martin)
>
> ----------------------------------
> Non-MV Joined-table:
> Id(1) & Name(Tom) & Car(Nissan) & Designed(Japan)
> Id(1) & Name(Tom) & Car(Porsche) & Designed(Italy)
> Id(2) & Name(Bob) & Car(Aston Martin) & Designed(UK)
>
> MV person-table:
> Id(1) & Name(Tom) & Car(Nissan) & Car(Porsche) & Designed(Italy) &
> Designed(Japan)  ???????????????
> Id(2) & Name(Bob) & Car(Aston Martin) & Designed(UK)

Cool, all that theory-talk has devolved into actual examples. Now I can play but I have no NULLs to bring to the party :)

(new 'designedIn 'verb)

(new 'japan 'country)
(new 'italy 'country)
(new 'uk 'country)

(new 'nissan 'car)
(set nissan designedIn japan)

(new 'porsche 'car)
(set porsche designedIn italy)

(new (set 'aston 'martin) 'car)
(set (. 'aston 'martin) designedIn uk)

(new (set 'john 'doe))

(new 'tom 'person)
(set tom has nissan)
(set tom has porsche)

(new 'bob 'person 'lawyer)
(set bob has (. 'aston 'martin))

Now, how do either handle the following without NULLs or schema evolution or impact on pre-existing queries?

(new 'yugo 'car)

(new 'prius 'car)
(set prius designedIn japan)
(set prius designedIn italy)

(set bob has yugo)
(set bob has prius)
Received on Sun Jan 14 2007 - 18:22:00 CET