Re: What is a "tuple"

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От Jan Wieck
Тема Re: What is a "tuple"
Дата
Msg-id 200106251132.f5PBWx207870@jupiter.us.greatbridge.com
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Ответ на Re: What is a "tuple"  ("Ross J. Reedstrom" <reedstrm@rice.edu>)
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Ross J. Reedstrom wrote:
> On Fri, Jun 22, 2001 at 06:31:03PM +0200, Kristoff Bonne wrote:
> > Greetings, (and also Alex)
> >
> > On Fri, 22 Jun 2001, Josh Berkus wrote:
> > > > Excuse my lack my 'database'-jargon, but what is a 'tuple'?
> >
> > > Also known as a "Record", or a "Row".  The word "tuple" is used because
> > > it can refer to a row returned as part of a result set as well as a
> > > record in a table.  Strictly speaking, a row returned from most queries
> > > is not a record, as that row does not exist in permanent storage
> > > anywhere .... it is created by the query.  Hence, "tuple".
>
> It's probably a back formation from the suffix 'tuple' as in the sequence:
>
> single, double, triple, quadruple, quintuple, sextuple, septuple, ...
>
> So, mathematicians generalized this (as is their wont) to
>
> [algebraic expression]-tuple, such as:
>
>         n-tuple, (n^2)-tuple
>
> Which found their way to The Relational Algebra, simplified to just
> 'tuple' and hence, to SQL.
>
> Ross (way to much detail!) Reedstrom
   At least it's for sure detailed enough :-)


Jan

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