The document discusses 3-tier architecture, which separates an application into three logical layers - the presentation layer, business logic layer, and data layer. It describes how this architecture evolved from earlier single-tier and dual-tier models. The 3-tier model provides advantages like scalability, reusability, security, and availability. While more complex than 2-tier, it allows for improved performance in medium to large systems by distributing the application across servers. An example is provided of implementing a 3-tier application using ASP.NET with distinct presentation, business, and data access layers.

1. 3- tier Architecture Sanjeev Sarma, Webx

2. Topics Covered What is 3-tier Architecture? Evolution of 3-tier Architecture Development. What does 3-tier Architecture Offer You? Advantages & Disadvantages An Example of how to implement 3-tier Architecture in .Net Platform Using C#

3. What is 3-tier Architecture? A three-way interaction in a client/Server environment The User Interface is stored in the Client. The Business Application Logic is Stored in one or more Servers. The Data is Stored in a Database Server.

5. Evolution to the 3-tier Architecture Tiers we are going to study

6. Single Tier Architecture Time of Huge “Mainframe” All Processing in Single Computer All Resources Attached to the same Computer Access Via Dumb Terminals

7. Single Tier – Advantages & Disadvantages Advantages Simple Efficient Uncomplicated Disadvantages Very Expensive

8. Dual Tier Architecture The Personal Computer Necessity of Providing Personal Software The Client Server Model was Born!! Logical System Components – Most of which are on the Client

9. Dual Tier – Advantages & Disadvantages Advantages Less Expensive than Mainframe Disadvantages The Connections to the Database Server are very Expensive One can only connects a limited number of users to a server before Database Server spends more time managing connections than processing requests Cost-ineffective. Many users only use their connections 2-3% of the time.

10. 3-Tier Architecture These Applications runs on the Traditional Client/Server Model But from a Application server. Client only Displays the GUI and data, but has no part in producing results Database Server Serves to few Connections

11. 3-Tier Advantages Scalability The Application Servers can be deployed on many machines The Database no longer requires a connection from every client. Reusability If a standard object is employed, the specific language of implementation of middle tier can be made transparent. Data Integrity The middle tier can ensure that only valid data is allowed to be updated in the database.

12. 3-Tier Advantages Improved Security Since the client doesn’t have direct access to the database, Data layer is more secure. Business Logic is generally more secure since it is placed on a secured central server. Reduced Distribution Changes to business logic only need to be updated on application servers and need not to distributed on clients Improved Availability Mission Critical Applications can make use of redundant application servers and redundant application servers, so it can recover from network of server failures.

13. 3-Tier Disadvantages Increased Complexity / Effort In General 3-tier Architecture is more complex to build compared to 2-tier Architecture. Point of Communication are doubled.

14. Conclusions Complex business rules easy to implement in application server layer. Business Logic off-loaded from database server and client, which improve performance Changes to business logic automatically enforce by server. All tiers can be platform independent. Superior Performance for medium to High Volume Environments

15. 3-Tier Application in ASP.NET The Program is organised into three major distinctive tiers or layers: Presentation Layer (User Interface) Business Layer (Business Access Layer) Data Layer (Data Access Layer)

16. User Interface Layer

17. Presentation Layer

18. Business Access Layer - Properties

19. Business Access Layer

20. Data Access Layer

21. Presentation Layer Creating an Object of Property Layer

22. Presentation Layer Creating an Object of Business Layer

23. Presentation Layer Data Object to Receive Data sent by Business Layer

24. Presentation Layer Obtaining ID from Property Layer

25. Presentation Layer Calling Business Layer Function

26. Business Access Layer Calling Data Layer Function

27. Data Access Layer Result Object Declaration

28. Data Access Layer SQL Query Definition

29. Data Access Layer Creating Object to receive data

30. Data Access Layer Query Execution

31. Data Access Layer Returning the Information of the Database

32. Business Access Layer Retuning the Information of Data Layer

33. Presentation Layer Returning Data From Business Layer

34. Presentation Layer Displaying Result

35. Questions & Answers If Any?

36. Thank You!