Re: hamsterdb Transactional Storage (thanks to all of you)
Date: Tue, 20 Oct 2009 18:39:11 -0700 (PDT)
Message-ID: <715e0d9a-2f8e-458d-ba5a-c3b2fd411008_at_a37g2000prf.googlegroups.com>
On Oct 15, 6:22 pm, paul c <toledobythe..._at_oohay.ac> wrote:
> com..._at_hotmail.com wrote:
>
> ...
>
> > By NEST I just meant Date & Darwen's GROUP. The operands are a
> > relation and a quoted-expression.
> > ...
>
> If you're going to refer to those guys, you should stick to what they
> say. Their GROUP operands are relations/relvars and attributes. Their
> NEST involves tuples.
I started off writing about nested relations and though I mentioned
D&D
I didn't think it mattered what they happened to call NEST/UNNEST.
Later I pointed to an example by them so there
I tried to indicate they use GROUP/UNGROUP not NEST/UNNEST.
The operator whose operands were in question was UNGROUP/UNNEST.
For unnesting a single attribute its operands
are a relation and an attribute name.
The value of any relation expression, possibly involving relvar names,
denotes the relation operand.
I referred to the attribute name as being a quoted expression because
it is passed on as-is without evaluation to the series operator.
Sorry about not being clear.
philip Received on Wed Oct 21 2009 - 03:39:11 CEST