Re: Business-logic in 3-tier architecture

From: Alfredo Novoa <alfredo_at_nospam_ncs.es>
Date: Sat, 12 Oct 2002 20:22:03 GMT
Message-ID: <3da88466.510794@news.wanadoo.es>

On Wed, 09 Oct 2002 23:40:24 GMT, "Arthur Yeo" <ayeo_at_acm.org> wrote:

>Theoretically, everyone knows that business logic is supposed to be in the
>middle-tier according to the 3-tier architecture. This seems to be
>counter-intuitive to Active Database concepts such as putting business logic
>in triggers with help from store procedures in the DBMS (which are all in
>the 3rd-tier of the 3-tier architecture.)

The 3 tiers are at implementation level not at logical level.

Logically there are still 2 tiers: client applications and the DBMS, but the logical DBMS has 2 physical tiers: the middleware and the SQL-DBMS. All business logic should be in the logical DBMS.

With a relational DBMS triggers are not needed because you can enforce all business logic declaratively in a much better way.

Sadly, in a lot of cases the logical DBMS is not a relational DBMS.

In the worst cases the logical DBMS is a specific purpose object (network) DBMS that uses an SQL-DBMS behind the scenes as a physical storage system.

Alfredo Received on Sat Oct 12 2002 - 15:22:03 CDT