Re: Application logic and Business logic

From: Dmitry A. Kazakov (mailbox_at_dmitry-kazakov.de)
Date: 03/06/05 

Date: Sun, 6 Mar 2005 16:00:02 +0100

On Sun, 06 Mar 2005 12:51:50 +0100, Alfredo Novoa wrote:

> On Sun, 6 Mar 2005 10:36:43 +0100, "Dmitry A. Kazakov"
> <mailbox@dmitry-kazakov.de> wrote:
>
>>I don't need them. 70% of types I am working with have no relational
>>operations defined on them. 20% have rather marginal use of it. 10% require
>>a substantial use in various containers.
>
> "Relation" is the unique logical container needed to manage data.

Relation is not a container, it is a function. Then I see nothing unique in
it.

> If you only use relations as containers the data management is
> radically simplified. And of course you will need the relational
> operators to manage relations.

Relation = relational operator = a Boolean function defined on the square
product of a set.

>>> declarative constraint definition,
>>
>>Good thing. I am extensively use constrained subtypes in Ada. Though it has
>>pitfalls (substitutability).
>
> But relational constraints are a lot more powerful.

Why do you think so?

>>> declarative derivation rules, the security system,
>>
>>Very
>>impressive indeed. I saw nothing more elaborated than that. I saw no ADTs
>>with different protection levels interacting with other ADTs in different
>>safety rings.
>
> No it is about users that should not see data that they are not
> authorized to see. And it is also about auditing all the acesses to a
> database.

So, so. That outdated primitive all-or-nothing approach. Safety cannot be
achieved that way.

>>> the separation between the physical and the logical levels,
>>
>>Are you talking about controlling HD heads?
>
> No, I am talking about abstraction. Application programmers don't need
> to know anything about the hardware.

Neither they should know about tables, columns etc.

>>> the automatic optimization,
>>
>>God save us from that. I even don't use GC.
>
> This is essential to rise the productivity level.
>
> Good DBMS's are self programming systems. A very important part of the
> "coding" can be automated. You introduce the specification and the
> program (AKA plan) is created in microseconds.
>
> Some coders don't like a lot that feature. :)

I heard that many times in many places! You press a button and yacc creates
a compiler, you press a button and the GUI builder creates an application,
you press a button and a UML tool generates code. Leave that fairy story to
managers... (:-))

>>> the automatic physical database design,
>>
>>It is pretty automatic, when you have no DB to design ...
>
> You always have phyisical DB design. Your disk or memory structures
> are physical DB designs. Don't you use graphs, arrays, linked lists,
> etc?

I do, I also don't believe that the AI of your or any other tool is strong
enough to generate something better than any 7 years-old imbecile can
write...

>>> the centralization of the integrity rules,
>>
>>Something tells me that centralization is a bad thing...
>
> Centralization is often a good thing. Although it is easy to guess why
> you don't have a lot of sympathy for the term :-)
>
> Would you like to have a different law system in each city block?

It is not the law system which enforces the integrity of our society, but
the propaganda of mass media, social instinct, hatred against pedestrians
and the government with its tools of oppression. These are quite
decentralized. You might be surprised to know the places where you can find
a policeman! (:-))

>>> the metadata management, the transaction
>>> control, the backup and recovery control etc, etc?
>>
>>Application backup?
>
> Automatic data backup and many other things.

It is not same. 

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de