Re: hamsterdb Transactional Storage (thanks to all of you)

From: <>
Date: Tue, 20 Oct 2009 18:39:11 -0700 (PDT)
Message-ID: <>

On Oct 15, 6:22 pm, paul c <> wrote:
> 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.

To "nest" is the generic term in the sense of nested tuples and relations.
D&D GROUP attributes into nested relations and WRAP attributes into nested 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

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