My Linux Stuff - Complete Blog For Linux Articles

My Linux Stuff - Complete Blog For Linux Articles

A Website For Complete Linux OS,Step by Step linux Installtion, Linux Tips and Tricks and Linux Stuff and so on... Connect and sharing here....

TOP 50 ENGINEERING COLLEGES IN INDIA 2014

TOP 50 ENGINEERING COLLEGES IN INDIA 2014

This below survey was taken many form many colleges in India. These Top 50 Engineering Colleges in India have Good Infrastructure, Good Environment, Educations , Staff, Placement , Research Activities and other Facilities are good.

Top 10 Government Engineering Colleges in India

Top 10 Government Engineering Colleges in India

These Government Engineering Colleges in India are really good for all kind of stuff like Education , research , Placement and New Innovation Ideas etc... But Getting seat in these colleges are heavy competition in students .....

Top 10 Colleges In India 2014

Top 10 Colleges In India 2014

Indian Institute Of Technology Delhi,Indian Institute Of Technology Bombay,Indian Institute Of Technology Kanpur,Indian Institute Of Technology Madras,Indian Institute Of Technology Kharagpur,Indian Institute Of Technology Roorkee,University Of Delhi,Indian Institute Of Technology Guwahati,University Of Calcutta,University Of Mumbai, National Institute Of Technology,Trichy.

2014 LATEST SURVEY TOP RANKING ENGINEERING COLLEGES IN INDIA

2014 LATEST SURVEY TOP RANKING ENGINEERING COLLEGES IN INDIA

This below survey was taken many form many colleges in India. These Top 100 Engineering Colleges in India have Good Infrastructure, Good Environment, Educations , Staff, Placement , Research Activities and other Facilities are good. If you want to do Engineering as your dream and try out these colleges

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Thursday, September 29, 2011

3 Tier Architecture (n-tier Arch)


Layered development or multi-layer development refers to a development model where presentation, business logic and data are separated. This brings many advantages, including cleaner code, increased maintainability and the ability to spread your application's load over multiple servers. In the discussion of layered design, you often see both the terms layer and tier. Generally, layer refers to a conceptual separation of the application, while tier defines physical boundaries. This article talks mainly about layers and presents a design where quite often most layers run on the same physical system, with some of them even in the same process space.
To get a general understanding of what a multi layered application looks like, consider the following diagram that shows a number of possible layers in a system. 

                                            Overview of Different Layers in a System 
Figure 1 - Overview of the Different Layers in a System
This diagram describes a general process of an application that presents data that comes from a database. The application, like a web site or a Windows Forms application is usually called the Presentation layer. Then in the middle, you find the Business Logic Layer, or the BLL that is the bridge between the Presentation layer and the next layer: the Data Access Layer or the DAL. This DAL then talks to the database to perform selects, inserts, updates and deletes.
One of the ideas of this design is that you can replace one or more of the layers without affecting the others. So, you could for example drop the web site as the presentation layer and replace it with a Windows Forms application. This change wouldn't require a change in any of the other layers. Similarly, you should be able to remove a SQL Server specific DAL and replace it with an Oracle or Microsoft Access version without the Presentation layer even noticing the difference.

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