How to implement a three layered serivces application

[Guest]

Hi,

I've been reading about three layered serivces applications
(http://msdn.microsoft.com/library/d...us/dnpatterns/html/ArcThreeLayeredSvcsApp.asp)

Now wonder how this fits all together..., am I thinking right, when I say:

You have a DLL for data access components (DAC), which take care of the
database interaction.

You have a DLL for business entities (BE), which references the DAC for CRUD
operations....

You have a DLL for Business Components (BC) which references the BE This
means just checking values etc. of the business entities and check if they
can be saved, updated, etc.

You have a DLL for BW, which actually just references the BC to set all the
business rules in one correct order?

You a facade layer which references all BE; BC and BW? How do you implement
this layer so that it's easy to program the UI?

And are UI Process Components just the Code Behind Files? And what do you
need to reference from here? Also BE, BC and BW or only the facade layer? How
do you get your objects then? What is the use of the facade layer then?

And how about the Security, OM and Communication? Are these just
helperclasses? I would like to get more a more technical view at this
theoretical documentation....

 

[Claudio Grazioli]

On Wed, 16 Mar 2005 17:49:02 -0800, GoofyIdiot wrote:

Hi Goofy

Hi,

I've been reading about three layered serivces applications
(http://msdn.microsoft.com/library/d...us/dnpatterns/html/ArcThreeLayeredSvcsApp.asp)

Now wonder how this fits all together..., am I thinking right, when I say:

You have a DLL for data access components (DAC), which take care of the
database interaction.

You have a DLL for business entities (BE), which references the DAC for CRUD
operations....

You have a DLL for Business Components (BC) which references the BE This
means just checking values etc. of the business entities and check if they
can be saved, updated, etc.

You have a DLL for BW, which actually just references the BC to set all the
business rules in one correct order?

You a facade layer which references all BE; BC and BW? How do you implement
this layer so that it's easy to program the UI?

And are UI Process Components just the Code Behind Files? And what do you
need to reference from here? Also BE, BC and BW or only the facade layer? How
do you get your objects then? What is the use of the facade layer then?

And how about the Security, OM and Communication? Are these just
helperclasses? I would like to get more a more technical view at this
theoretical documentation....

Well, I'd say a lot of questions for a simple news message to answer! That
would fill books!
I strongly suggest you to read one of the books of Rockford Lhotka about
business objects (and multi-tier applications). His has two books, one for
VB.NET programmers and one for C# programmers. Reading his book (and it's
fun to read because very well written) and your questions are all answered
and you even get a multier-tier open source framework with it, ready to use
for basic n-tier application development.

Visit his web page to get more information on the books:
http://www.lhotka.net

 

[Guest]

daClaudio,

I have read the book (VB version, while I program mostly C#). Anyway, the
only thing in this book that I have read, is about Business Entities,
Business Rules of those Entities and the daL part. That part I get from the
book.

I have the feeling the the OM, Security and Communication are helper classes.

What I don't get is how to implement the Workflow and the facade layer....Do
you have any references to that? Another book maybe?

And was I right the the ProcessUI is all in the code behind files?

Greetings