Re: Front End or Backend - Where to put what?

From: Craig Alexander Morrison (reply_at_newsgroups.com)
Date: 09/24/04 

Date: Fri, 24 Sep 2004 07:26:44 +0100

Unless you are using SQL Server, DB2 or Oracle you can forget your three
layers.

If you are using Jet then _just_ get the design of the database right (and
use field and table validation as much as possible). This means normalise
the data for that business. Many people make the mistake of thinking that
there is only one way to normalise the same data in different businesses, I
have designed several general insurance systems and the design of the
database with essentially the same data can be significantly different
depending on the business and the way that business handles the data. Many
business rules can be accommodated in the actual design of the database
itself. When normalising the data ensure that you are looking at the
business and not the real world (the real world is too complicated).

The Access applications should not contain any constraints that can be
applied in Jet. If anything the constraints in the applications should be
inside the constraints in the database. E.g. a specific field in the
database can have values in the range 0 to 10,000,000 however a particular
application may only be permitted to record in the range 2,000 to 200,000.

BTW You are not running Access at both ends, per se, Access only runs on the
workstation and can access a file from a server. The back-end is just a file
on a file server. 

--
Slainte
Craig Alexander Morrison
"BigDuke6UK" <BigDuke6UK@discussions.microsoft.com> wrote in message
news:7860B16B-0C6A-4BD9-B5B7-16D8257E5966@microsoft.com...
> First of all thanks for your replies.
> I intend to run Access at both ends so it seems my approach as already
been
> decided i.e queries and code go at the Front End. However a further
confusion
> on my part is the tiered approach of 'Data Layer, Business Layer and
> Application Layer'. My thoughts were to seperate 'data access' code and
> relevant objects from the 'presentation code' relating to Form events and
> reports and somwhere in between the two have the 'application layer'
dealing
> with all the business logic such as large scale queries, functions and
> procedures and basically all the behind the scennes stuff the application
is
> being built for. I think I may be in danger of thinking too much and
> confusing myself with abstract concepts and what is actually acheivable.
Any
> further comments?
> Thanking you in advance.
>
> "BigDuke6UK" wrote:
>
> > I am designing a fairly large scale Access 2003 application. I intend to
have
> > a front end for around 20 clients and a server backend. Server is
running Win
> > 2003 Server and clients XP Pro. I am confused as to where I should put
my
> > code and stored queries, on the front end with the table data or on the
> > backend. I have two very good books by my side but they contradict each
> > other. Also a programmer friend of mine says that all queries and code
used
> > to access the data tables should be kept at the front end data layer but
my
> > thinking is that queries and code should take place at the back end in
order
> > to spare the server unecessary workload. Any help would be greatly
> > appreciated as I am going round in circles at the moment.
> >

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