Re: Cartesian joins
From: Ram Raman <veeeraman_at_gmail.com>
Date: Tue, 2 Apr 2019 15:25:14 -0500
Message-ID: <CAHSa0M3Zz4W-6D20n4rexXeSphu6S7KrfAAyAMmQov9xM0LfhQ_at_mail.gmail.com>
Date: Tue, 2 Apr 2019 15:25:14 -0500
Message-ID: <CAHSa0M3Zz4W-6D20n4rexXeSphu6S7KrfAAyAMmQov9xM0LfhQ_at_mail.gmail.com>
I am not a big expert on joins, but I think Oracle chooses Cartesian when
it thinks one of the row sources is going to return only one row.
On Sat, Mar 30, 2019 at 3:08 PM Orlando L <oralrnr_at_gmail.com> wrote:
> List
>
> When is it OK to do Cartesian joins?
>
> 1) It looks like during the star transformation while joining 2 or more
> small result sets from dimension tables?
>
> 2) In an ordinary join, when one of the row sources is estimated to be 1
> row with the other row source be several thousand? In this case, the
> Cartesian will be just 1*no of rows in the other table.
>
> Any explanation is helpful. thanks
>
> Orlando.
>
>
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Received on Tue Apr 02 2019 - 22:25:14 CEST