subhashini
(Moderator): hello everybody :) a very good evening to
all of you ! subhashini (Moderator):
Welcome to today's chat on Model View Controller Babu:
good evening to all.... subhashini (Moderator):
we have Pooran Prasad ( MVP ) with us today. subhashini
(Moderator): To give you a quick intro about him subhashini (Moderator): R Pooran
Prasad is currently undergoing grooming program at NirmaLabs [ <http://www.nirmalabs.com>
]. Before that, he has worked for Itreya Technologies Pvt Ltd [ <http://www.itreya.com>
] for 3½ years. During his stay at Itreya, the open work culture
and very supportive environment helped him to learn and hone his skills
on latest Microsoft technologies, and share the same within the organization
and communities. He has worked on almost all the Microsoft related
projects in Itreya, including 3 products from inception to deployment.
He is currently undergoing business training and will like to keep
in touch with technology and help the Indian communities flourish
leaps and bounds. Contact him at itzpooran@msn.com subhashini (Moderator): Before
we start a few chat rules as always subhashini
(Moderator): Please refrain from sending any private messages
to the expert during the chat subhashini
(Moderator): Chat Procedures:
This chat will last for one hour. During this hour, our Experts will
respond to as many questions as they can. Please understand that there
may be some questions we cannot respond to due to lack of information
or because the information is not yet public. We encourage you to
submit questions for our Experts. subhashini
(Moderator): We ask that you stay on topic for the duration
of the chat. This helps the Guests and Experts follow the conversation
more easily. We invite you to ask off topic questions after this chat
is over. subhashini (Moderator):
Please use the radial button "submit a question " to ask
any questions to the expert subhashini
(Moderator): So let's get the chat rolling and let's welcome
Pooran subhashini (Moderator):
Hi pooran :) the stage is set ... Pooran_MVP
(Expert): : Hello Everybody .. Thanks for coming :) suchi: hi pooran Prash: Hi Poori :) Pooran_MVP (Expert):
Today, we will discuss MVC pattern, its uses and implementation details Pooran_MVP (Expert): : I suppose
the audience has worked on Web applications/Windows applications using
.Net platform Babu: ya...ofcourse Pooran_MVP (Expert): : To give
a brief intro about MVC pattern.. Pooran_MVP
(Expert): : The Model View Controller pattern was invented
in a Smalltalk context for decoupling the graphical interface of an
application from the code that actually does the work. Pooran_MVP
(Expert): : To put it in simple terms .. Pooran_MVP
(Expert): : Input --> Processing --> Output
Controller --> Model --> View Pooran_MVP
(Expert): : Lets get deep in to each of these Pooran_MVP
(Expert): : VIEW
View is the graphical data presentation (outputting) irrespective
of the real data processing. View is the responsible for look and
feel, some custom formatting, sorting etc. View is completely isolated
from actual complex data operations. Pooran_MVP
(Expert): : It is what user sees. Pooran_MVP
(Expert): : CONTROLLER
Controller is responsible for Notice of action. Controller responds
to the mouse or keyboard input to command model and view to change.
Controllers are associated with views. User interaction triggers the
events to change the model, which in turn calls some methods of model
to update its state to notify other registered views to refresh their
display. Pooran_MVP (Expert):
: Through controller, user interacts with the application Pooran_MVP
(Expert): : MODEL
Model is responsible for actual data processing, like database connection,
querying database, implementing business rules etc. It feeds data
to the view without worrying about the actual formatting and look
and feel. Pooran_MVP (Expert):
: This is underlying data from database/xml/app config etc. Pooran_MVP
(Expert): : Are there any questions till now? k:
Hi pooran, Now Can you give simple example where we can visualize
this in an .Net Web App Bijoy: SO MODEL is equivalent
to all other tiers Pooran_MVP
(Expert): : Well, asp.net pages are the best examples. k: So Is It like component Class->Code
behind->Page subhashini (Moderator):
Hi k, could you please use the radial button "submit your question"
to ask a question, else the expert would not be able to answer them
easily Pooran_MVP (Expert):
: yes. in asp.net, .aspx page acts as view, .aspx.vb/.aspx.cs act
as controller and your dataset acts as your model subhashini
(Moderator): request all of you to please use the "submit
a question" radial button to ask any question Pooran_MVP
(Expert): : Bijoy, Model is your data. Usually, in medium
and large applications, we do have separate Database classes where
database access is through functions like getData, setData Pooran_MVP
(Expert): : Asp.net provides 2 tier architecture. However,
we can write components for controller and database classes to make
it much extensible Pooran_MVP (Expert):
: Lets proceed with advantages of MVC pattern Pooran_MVP
(Expert): : 1.Since MVC handles the multiple views using
the same enterprise model it is easier to maintain, test and upgrade
the multiple system.
2.It will be easier to add new clients just by adding their views
and controllers.
3.Since the Model is completely decoupled from view it allows lot
of flexibilities to design and implement the model considering reusability
and modularity. This model also can be extended for further distributed
application.
4.It is possible to have development process in parallel for model,
view and controller.
This makes the application extensible and scalable. Pooran_MVP
(Expert): : While architecting the application, much care
has to be taken to design the application to get maximum performance
and scalability Pooran_MVP (Expert):
: with MVC pattern, we can make it possible Pooran_MVP
(Expert): : However there are some drawbacks Pooran_MVP
(Expert): : 1.Requires high skilled experienced professionals
who can identify the requirements in depth at the front before actual
design.
2.It requires the significant amount of time to analyze and design.
3.This design approach is not suitable for smaller applications. It
Overkills the small applications. venkat
Murthy: Pooran, other than limitations of smaller applications,
are there any benchmarks for MVC pattern. Like, when should we go
for MVC, when not. Pooran_MVP (Expert):
: Venkat, As I told earlier, if we have architect in team or any professional
with knowledge of implementing MVC pattern, it could be of help. There
aren't any benchmarks I have come across Pooran_MVP
(Expert): : Designing apps requires quite a bit of time
of development cycle. Most of the times 1/3 of time should go into
designing application. Practical experience of object oriented application
development is must DMk: But
why is this approach not suitable for smaller applications? Pooran_MVP
(Expert): : By smaller applications, I mean POCs [ Proof
of concepts] and applications with less than 10000 lines of code.
Most of the times it will not be necessary to implement MVC pattern
in such cases Pooran_MVP (Expert):
: any more questions? request all of you to please use the "submit
a question" radial button to ask any question venkat
Murthy: Thnx Pooran. Since we've lot of architecting
models
(Zachman, MDA.. etc), I was just curious enough to learn weather it
could be of any use to apply MVC to a set of project types. Say for
example, Zachman is recommended for EAI applications etc. venkat
Murthy: Correct me if i am wrong Pooran_MVP
(Expert): : If you are using ASP.Net to develop, you are
using part of MVC pattern already. Pooran_MVP
(Expert): : And most of the times, we use mix of patterns
in an applications. I have used this pattern in more than 4 projects Pooran_MVP (Expert): : One of
them is EAI application and it works wonderfully Pooran_MVP
(Expert): : I hope that answers your question Jeya:
Hi, We are developing an web based application using ASP.NET. We have
done the business logic using C# in an Lib. We imported the Dlls and
Business Access layer to our VS.NET. All the database transactions are
through Stored Procedure. Do see is it correct? Jeya:
Does this fit into MVC pattern ? Pooran_MVP
(Expert): : 100% Pooran_MVP
(Expert): : This is the best example for MVC pattern Jeya: Thanks. Pooran_MVP
(Expert): : In windows application world, this concept
is not there by default. It is recommended to create components for
data access. Pooran_MVP (Expert):
: Recently we designed an application where a model and controller
component which was shared by both windows application and a related
web application. pradeep TP:
hi all. may i know whether this chat is in progress. Pooran_MVP
(Expert): : Are there any more questions so far? Pradeep,
yes it is. k: Actually can
we Call the DAL the MODEL or the BLL Pooran_MVP
(Expert): : Yes we can. k:
Both? Pooran_MVP (Expert):
: Yes. However, it is cautioned that considerable amount of time has
to be spent before considering DAL and BLL. pradeep
TP: Pooran, where can i get the chat script of today's
chat. I entered the chat room late. Pooran_MVP
(Expert): : Yes you can. Will be put up on the site. pradeep TP: can i know whether
there are any other web application architecture widely used in development. Pooran_MVP (Expert): : K, if it
is a medium sized application, and time is limited, it is preferred
to develop custom components as understanding DAL and BLL will take
time. If you have already worked on DAL and BLL, please go ahead and
use them. For others who don't know DAL and BLL, it is Business Logic
Layer (BLL) and Data Access Layer (DAL) k:
So Can we consider the Microsoft DataAccess Application Block as MODEL
Pooran_MVP (Expert): : K,
yes you can. Pooran_MVP (Expert):
: Pradeep, There is maverik, zachman, mda, WebWork.. there are many
of them Pooran_MVP (Expert): : http://mavnet.sourceforge.net/
is one implementation for .net Pooran_MVP (Expert): : variant
of MVC pradeep TP: thats great
pooran. thank you . can you recommend any particular architecture
which you think has worked for you most of the time. Pooran_MVP
(Expert): : I have worked with MVC pattern in almost 4
completely different projects. It works just fine. I am trying out
Maverick for one project now subhashini
(Moderator): We have the last 7 mins for the chat to conclude subhashini (Moderator): So please
rush your queries to Pooran Pooran_MVP
(Expert): : In one application which needed access to java
pates, where we had used struts Pooran_MVP
(Expert): : Any more questions pradeep
TP: pooran thank you for the answers. i am looking forward
for the chat script. k: So
can we conclude that a 3-tier App is on MVC Pooran_MVP
(Expert): : Welcome Pradeep k:
Thanks Pooran Pooran_MVP (Expert):
: K, It is partly right. Even a 2 tiered or multi tiered application
can be called MVC. Pooran_MVP (Expert):
: As you said, you are using BLL and DAL in web application. That
constitutes 4 layers as we have 4 tiers k:
Ya ofcourse.. Pooran_MVP (Expert):
: If it is simple asp.net application, our model is nothing but our
dataset object which holds data Pooran_MVP
(Expert): : Are there any more questions? pradeep
TP: do we have a second part of the session? k:
Is It advisable to use Com+ Enterprise Services (for Transactions)
in .Net web apps, or any disadvantage Pooran_MVP
(Expert): : We are planning for a session in BDotNet, Bangalore's
user group where we take a sample application to explain the MVC pattern.
pradeep TP: when is that
session going to happen? Pooran_MVP (Expert): : Pradeep,
sometime this month. Will let you know soon. keep watching http://groups.msn.com/bdotnet Pooran_MVP
(Expert): : k, the question is offtopic. However, the answer
is, as Com+ enterprise services are to used with interop in .Net applications,
which may give some performance issues, it is quite advisable to recode
the services in .Net k: Thanks
Pooran Pooran_MVP (Expert):
: Welcome K Pooran_MVP (Expert):
: One last question before we wind up subhashini
(Moderator): So time's up! subhashini
(Moderator): and that brings us to the end of this chat subhashini (Moderator): Please
email Pooran for any additional queries pradeep
TP: what is Pooran's email address subhashini (Moderator): at itzpooran@msn.com subhashini
(Moderator): Hope the chat was useful and informative for
all of you. subhashini (Moderator):
Thanks for taking out time from your hectic schedule.. k:
Thanks subhashini and Bye All Pooran_MVP
(Expert): : I suppose the MVC pattern as a concept is quite
clear by now and this chat was informative. Feel free to attend the
DotNet session for a practical example. Thanks for coming to this
webchat. subhashini (Moderator):
and a big thanks to Pooran for hosting this chat subhashini (Moderator): Please
feel free to pool in your feedback at commind@microsoft.com Pooran_MVP (Expert):
: Thanks to Subhashini making this happen and bye to all subhashini
(Moderator): Have a lovely evening :)
