Re: What predicates the following relation represents

"robert" <gnuoytr_at_rcn.com> wrote in message news:da3c2186.0405070417.323ba2b8_at_posting.google.com...
> > I gather now that you are talking about whether the language(s)
associated
> > with database-centric software applications should be declarative,
> > procedural, OO, etc, right? Isn't the "comprehension of the data" in an
> > RDBMS "encapsulated inside some inaccessible object" from the
perspective of
> > somone who doesn't know the declarative language?
>
> oh please, stop it. sql has been codified since 1986. updated along the
> way, of course.

Yes, but...

There are other issues:

First, the metadata isn't the declarative language. It's the record of the effects of the DDL (if I'm understanding "declarative language" correctly.) So a person might understand CREATE TABLE and CREATE INDEX but not be able to make use of the data.

Second, the metadata has not been standardized until around 1992 (can you help here, Joe Celko?), and none of the databases I've seen in the "real world" conform to that standard. You have to know the system tables that are particular to the product, and parhaps to the version of the product.

Third, there are items that are critical to the interpretation of the data that just aren't in the metadata, except perhaps in the form of comments. In particular, if you take tables to be a representation of relations (skip the Torquemada response, please) the proposition asserted by each table is not specifically represented in the metadata. Without that, you can't really tell what the data means.

Having said all that, I think that Dawn is slowly arriving at the big reason why "the relational model" has not been the "silver bullet": ignorance. Received on Fri May 07 2004 - 15:37:19 CEST