Re: Object-relational impedence

David Cressey wrote:
...
>
> I thought that the SET clause of the UPDATE statement was an assignment in
> disguise.
> ...

I would have thought UPDATE itself is assignment in disguise and SET is just an arbitrary language device, just as scope operators don't seem to have much to do with database theory, ;). (I admit I have no idea whether UPDATE without SET is allowed.)

Regarding SICP, I think somewhere it states that FP languages don't have assignment, which I didn't see here, at least in the few OO cross-posts that I accidentally read.

As usual when replying to David C, no offence but can't resist mentioning that Date has claimed that the ACID property that SQL vendors tout is basically incomplete (my words, not his), I think he might have been including SQL's UPDATE when he said that.

Regarding scope, I even question some of the deep thinkers, such as Pascal, when they seem to imply that rdbms 'logic' requires persistence.   Maybe that's misrepresenting them but I've never seen any need for an algebra or calculus per se to include operators that have to do with persistence, as practical as they might be. For me, the greatest value of relational theory is from the point of view of the user and how he can test results in his head with merely a basic understanding of project and join and/or traditional first-order logic and without such users needing to concern themselves with how OO or machine techniques choose to obtain those results. Received on Mon Mar 10 2008 - 19:55:16 CET