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Re: globals besides relvars?

From: Paul Vernon <paul.vernon_at_ukk.ibmm.comm>
Date: Mon, 28 Jul 2003 18:57:54 +0100
Message-ID: <bg3oc0$1ec0$1@gazette.almaden.ibm.com>


"Marshall Spight" <mspight_at_dnai.com> wrote in message news:WqcVa.148132$GL4.38052_at_rwcrnsc53... [snip]
> For many things, a functional expression is better than the relational
> equivalent. For example, I'd rather invoke the getTimeZone() function
> than:
>
> Select * from TimeZone
> unwrap relation into tuple
> unwrap tuple into value

Marshall, you are arguing about syntax, but..

[snip]
> Okay, I'm talking about the logical model of things.

..claim to be interested in the logical model.

Syntax is mostly unimportant when at the logical level.

[snip]
> Don't functions have access to the database?

No.

> Or do some of them have this access?

No

> *Some* code somewhere has to be able to access the database,

Yes. Queries and Updates.

[snip]
> I'm groping my way towards a model where the concept of a
> programming language's global variables

The database is the only global variable. In fact it is the only varable *at all*.

If you do still want to talk about 'functions' that can access the global variable, then SQL table functions could be the place to start. They do things that you can't do with views, and their functionally is required in any good dbms IMO, but to my way of thinking, they are little more than macro expressions. Does suggest again that we need a better handle on how macros fit into things though.

Regards
Paul Vernon
Business Intelligence, IBM Global Services Received on Mon Jul 28 2003 - 12:57:54 CDT

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