Re: chooses not to generate code at all

On Mon, 22 Aug 2005 17:27:53 GMT, "H. S. Lahman"
<h.lahman@xxxxxxxxxxx> wrote:
>> I don't know how to turn that kind of statement into a decision
>> process, since any rule that is true, is as true as Maxwell's Laws.
>
>The issue is stability. Max's Laws haven't changed in quite awhile.

And who's fault is that?

>However, most business rules and policies are not so stable. I don't
>think any rules or policies that are at risk for needing maintenance (or
>whose scope of application may change) should be implemented as stored
>procedures.

Well, but that's surely too broad.

>[At least in the conventional sense where the procedure is triggered by
>specific database updates.

That would be a "trigger", not a "stored procedure" as such.

> In theory one could store code, parametric
>data, and whatnot in the DBMS that is selectively invoked by external
>applications. In that case those applications define the scope and
>context of execution rather than the DBMS' data. So in that case the
>DBMS is just a storage medium for the procedures and doesn't decide when
>they should be executed.]

That is exactly what a "stored procedure" is all about.

>In this context relational algebra provides a meta-meta-model.

Ouch, my head!

>SQL is
>an instance of that model representing the meta-model for those
>computing environments where one chooses to employ SQLServer for
>application implementations. If one is generating code for a particular
>application, then the Transformation Model is an instance of the SQL
>meta-model that provides the specific mappings necessary for the
>application context (e.g., FORTRAN array name to enterprise RDB table
>name). If development is manual, the developer supplies that mapping
>directly in the 3GL code (i.e., the Transformation Model is in the
>developer's head).

Er, yeah?

>An RDB is not "an MDA". It is simply a model instance that can be
>either an Input Model or an Output model under MDA, depending upon
>context. It happens to instantiate a meta-model, which is reflected in
>schemas, etc.. That meta-model instantiates a general data model
>especially tailored to persistence (Table, Tuple, Field).

I'm not sure that these abstractions are "especially tailored to
persistence". Certainly "field" is a general concept.

> The issue of content is more
>about maintainability and separation of concerns with respect to good
>software development practice.

Good practice is always good.

> IOW: render unto Caesar the things that
>are Caesar's and render unto the DBMS the things that are data storage.

No, that's just the mistake so many make today. To a first
approximation, a DBMS is not about data storage, it's about data
modelling, and the fact that some entity is implemented as a table
need not be transparent to users, and indeed for occult internal
reasons, there may be times when a 3NF entity is NOT stored as a
table. Soon as you think it's all about storage,

.... I call that sloth,
the first big step on the road to the depths of degreda
I say, first- medicinal wine from a teaspoon,
then beer from a bottle
And the next thing you know your son is playin'
for money in a pinchback suit
and listenin' to some big out-o'-town jasper
Hear him tell about horserace gamblin'
Not a wholesome trottin' race, no,
but a race where they set down right on the horse
Like to see some stuck up jockey boy sittin' on Dan Patch?
Make your blood boil, well I should say
....

http://www.niehs.nih.gov/kids/lyrics/trouble.htm

J.


.

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