Re: WWW/Internet 2009: 2nd CFP until 21 September
From: paul c <toledobythesea_at_oohay.ac>
Date: Fri, 14 Aug 2009 13:42:14 GMT
Message-ID: <WQdhm.41209$PH1.17717_at_edtnps82>
>
> Relational decomposition doesn't mean lossless projection. The decomposed
> relations can contain extra tuples that don't show up in a join.
> Referential constraints are needed to prevent the extra tuples.
> ,,,
Date: Fri, 14 Aug 2009 13:42:14 GMT
Message-ID: <WQdhm.41209$PH1.17717_at_edtnps82>
Mr. Scott wrote:
> ...
>> 1) in SQL, just what does decompositon of tables mean? Does it mean what >> relational decomposition means, ie., lossless projection, or something >> else?
>
> Relational decomposition doesn't mean lossless projection. The decomposed
> relations can contain extra tuples that don't show up in a join.
> Referential constraints are needed to prevent the extra tuples.
> ,,,
What is the difference between 'relational decomposition' and mere projection? Received on Fri Aug 14 2009 - 15:42:14 CEST