Re: Object-relational impedence
From: S Perryman <q_at_q.net>
Date: Thu, 06 Mar 2008 09:49:46 +0000
Message-ID: <fqoenv$fo4$1_at_news.datemas.de>
Date: Thu, 06 Mar 2008 09:49:46 +0000
Message-ID: <fqoenv$fo4$1_at_news.datemas.de>
> S Perryman <q_at_q.com> wrote in news:fqn0ir$mdg$1_at_aioe.org:
>>boolean f(Tuple t) { return (t.x = 123) ; }
>>Set<Tuple> S ;
>>Set<Tuple> t = S.match(f) ; // or match(S,f) if one prefers
>>1. How is the above not "set-oriented" ??
>>A set is given as input to a match operation which produces a
>>set as output.
>>2. I have no idea whatsoever *how* S performs the match by
>> looking at the above.
> 'Match' is cool, but what about more interesting operations like > 'project(join(R1,R2)), R1.a1, R2.b3)' where R1 is a set of <c,a1,a2,a3> > tuples and R2 is a set of <c, b1,b2,b3> tuples ? How do you express > that in your fav OO language ?
As I have said on numerous occasions, the semantics of "joins" are an issue for OO (specifically the fact that in OO any of the "values" of c/a1..a3/b1..b3 could be a computational operation and not a data value etc) .
Regards,
Steven Perryman
Received on Thu Mar 06 2008 - 10:49:46 CET