Re: Object-relational impedence
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Thu, 06 Mar 2008 13:16:20 -0400
Message-ID: <47d026e5$0$4043$9a566e8b_at_news.aliant.net>
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> 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) .
Date: Thu, 06 Mar 2008 13:16:20 -0400
Message-ID: <47d026e5$0$4043$9a566e8b_at_news.aliant.net>
S Perryman wrote:
>> S Perryman <q_at_q.com> wrote in news:fqn0ir$mdg$1_at_aioe.org:
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>>> boolean f(Tuple t) { return (t.x = 123) ; }
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>>> Set<Tuple> S ;
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>>> Set<Tuple> t = S.match(f) ; // or match(S,f) if one prefers
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>>> 1. How is the above not "set-oriented" ??
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>>> A set is given as input to a match operation which produces a >>> set as output.
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>>> 2. I have no idea whatsoever *how* S performs the match by >>> looking at the above.
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>> '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 ?
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> 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) .
How is that any different than a relational view? Whether the data is calculated or stored directly is irrelevant. Received on Thu Mar 06 2008 - 18:16:20 CET