Re: 70-300 exam question

Date: 03/08/04

Date: Mon, 08 Mar 2004 08:14:07 -0800

Rudolph Pienaar wrote:

> I am studying for exam 70-300 and am using the self pasted training
> book. On the included CD the practise exam has the following question.
> Where is the best place to implement the business rules in the data
> tier.
> The correct answer according to them is: In components in the
> business rules layer, and then the datalayer can call these
> components from the business rules layer.
> I disagree with this anwer. I think store procedures are the best way
> to implement business rules in the DATA TIER. Also if one has a multi
> tier atchitecture, then busines rules go to the business rules layer,
> but then the business rules layer calls the data layer, not the other
> way around.
> Does anybody have a comment on this?
> Regards
> Rudolph

You might have missed the assumption that they are using stored
procedures in addition to wrapper classes in the data tier.

Microsoft always assumes you are using stored procedures - unless they
are trying to showcase a particular problem with a design.

The purpose in custom wrapper classes in the data tier is to give your
business tier an easier way to interface to the data tier. The business
tier should not call stored procs directly in this kind of design.

Of course, there are always exceptions and I'm not a purest.

One hot idea now is to define custom collections to use for passing
data between the data tier and the business object layer. This allows
you to use data binding, and it keeps the use of stored procs
restricted to the data tier.