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>


S Perryman wrote:

> Yagotta B. Kidding wrote:
>

>> 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

>
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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.

>
>
>> '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) .

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

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