DOT NET Interview Questions - DotNetSpider

√
√
Payment
Invoicing
All the four modules when built at initial stage where built completely independent. The
main interaction between all these subsystems is customer placing order. This functionality
can be attained by using all these subsystems, which involves complex interaction between
them.
There’s where FAÇADE comes in to action. We have built a FAÇADE called as
“FACADEORDER” which sits on the top of all these subsystem and fulfills our
functionality.
(I) How can we implement observer pattern in .NET?
Observer patterns can be implemented using “Delegates” and “Events”. I leave this to
the readers to implement one sample code for observer patterns.
(B)What is three tier architecture?
The three tier software architecture emerged in the 1990s to overcome the limitations of
the two tier architecture.
There are three layers in when we talk about three tier architecture:-
User Interface (Client) :- This is mostly the windows user interface or the Web interface.
But this has only the UI part.
Mid layer: - Middle tier provides process management where business logic and rules are
executed and can accommodate hundreds of users (as compared to only 100 users with
the two tier architecture) by providing functions such as queuing, application execution,
and database staging.
Data Access Layer: - This is also called by the famous acronym "DAL" component. It has
mainly the SQL statement which do the database operation part of the job.
The three tier architecture is used when an effective distributed client/server design is
needed that provides (when compared to the two tier) increased performance, flexibility,
maintainability, reusability, and scalability, while hiding the complexity of distributed
processing from the user.
157