Re: 4 the FAQ: Are Commercial DBMS Truly Relational?
From: Marshall Spight <mspight_at_dnai.com>
Date: Sun, 10 Oct 2004 15:43:25 GMT
Message-ID: <xMcad.156343$wV.96061_at_attbi_s54>
Date: Sun, 10 Oct 2004 15:43:25 GMT
Message-ID: <xMcad.156343$wV.96061_at_attbi_s54>
"Laconic2" <laconic2_at_comcast.net> wrote in message news:Wv2dnSILNblTtPTcRVn-gg_at_comcast.com...
>
> "Marshall Spight" <mspight_at_dnai.com> wrote in message
> news:Yo2ad.220257$D%.89507_at_attbi_s51...
>
> > Right, but although you certainly need an operation like this,
> > SQL's outer join is not the only way to get it. I rather think
> > that GROUP/UNGROUP, and result columns of relation type,
> > are a better approach, in part because NULLs are not required.
>
> I'm not familiar with UNGROUP. Could you say some more, or give me a
> pointer?
Relation 1:
(1,a) (2,a) (2,b)
Relation 2:
(a) (b) (c)
R1 group R2:
({1,2}, a) ({2}, b) ({}, c)
Marshall Received on Sun Oct 10 2004 - 17:43:25 CEST