Re: RM's Canonical database

From: AndrewMackDonna <newsamd_at_amc.com>
Date: Mon, 03 Jul 2006 20:23:58 +0100
Message-ID: <e8bqsn$sm1$2@news.freedom2surf.net>

Marshall wrote:
> AndrewMackDonna wrote:

>> Marshall wrote:
>>> Ron Jeffries wrote:
>>>
>>>> In favor of putting a common rule in the DBMS is that it is centralized. The
>>>> "Once and Only Once", or "DRY" principle suggests that it should be there.
>>>>
>>>> Another possibility for a location for such a rule is in a middle tier, where it
>>>> can also meet the DRY principle.
>>> But then you lose the centralization.
>> Not necessarily, its moved thats all.  There is still only one instance
>> of it in the company.

>
> (Some clarification: I am assuming Ron is talking about the idea of
> having an application server "in front of" the dbms that implements
> business rules via whatever language the app server code uses;
> e.g. Java.)
>
> What you say would only be true if there was no update access
> to the dbms except through the app server. In practice, this is
> rarely the case; the larger the enterprise, the less likely this is
> to be true. Furthermore this approach introduces friction in the
> development process, because the app server interface is
> in practice always less flexible than a generic SQL interface,
> and every additional application requirement must be hand
> coded into the app server.
>
> In other words, this approach doesn't scale.

Hmmm.. I'd have to say I disagree, having seen it scale.

An example I think.....(off the top of my head)

http://www.google.com/apis/

>
>
> Marshall
>
Received on Mon Jul 03 2006 - 14:23:58 CDT