Re: Object-relational impedence

From: S Perryman <>
Date: Thu, 06 Mar 2008 09:49:46 +0000
Message-ID: <fqoenv$fo4$>

Yagotta B. Kidding wrote:

> S Perryman <> wrote in news:fqn0ir$mdg$

>>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) .

Steven Perryman Received on Thu Mar 06 2008 - 10:49:46 CET

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