Re: RM and abstract syntax trees

On Nov 1, 12:36 pm, Marshall <marshall.spi..._at_gmail.com> wrote:
> On Oct 31, 6:20 pm, David BL <davi..._at_iinet.net.au> wrote:
> > On Oct 31, 11:55 pm, Marshall <marshall.spi..._at_gmail.com> wrote:
>
> > > If we are using nested structures, then the structure itself
> > > provides the integrity.
>
> > Exactly, that's what I was trying to say. My somewhat vague notion
> > is that the RM representation loses that simplicity because it is *too
> > flexible* - hence the need for complex integrity constraints
>
> Sure.
>
> It is a general engineering truism that a solution designed for
> some specific narrow purpose may be better *at that purpose*
> than something general purpose.
>
> So it's no particular surprise that a structure of heterogeneous
> trees will model an application (parsing) of heterogeneous
> trees.
>
> We might prefer a general solution still, for general reasons.
> And I think we will also find that at least some queries are
> going to be easier with a relational approach even so.
> Off the top of my head ... oh, I dunno. Dump all the symbol
> names or something.

If it's indeed true that RM is too flexible for certain sub-problems, it would seem that from the perspective of RM those sub-problems where better niche solutions exist should be treated as opaque domain types.

Date seems to take this point of view : ie that the structure of domains is orthogonal to the relational model. Received on Thu Nov 01 2007 - 05:57:43 CET