This document compares 2-tier and 3-tier architecture. 2-tier architecture has a presentation layer on the client and data stored on a server, providing direct communication between the two. 3-tier architecture adds an application layer between the client and database server to process requests and business logic before communicating with the other layers. The 3-tier model is more popular as it provides benefits like improved performance, security, and scalability compared to the 2-tier architecture.

1. 2-Tier and 3-Tier
Architecture of ERP

2. SUBMITTED TO:
SUBMITTED BY:
Mr. Shobhit Kumar
Asst.Professor
S M Qamar Abbas
GUID: 19GSOB2010450
Batch: 4
Session : 2019-2020
Introduction to ERP & MIS
(MBDS5031)

3. 2-Tier Architecture
A two-tier architecture is a database architecture where
1. Presentation layer runs on a client (PC, Mobile, Tablet, etc)
2. Data is stored on a Server.
An application interface which is called ODBC (Open Database
Connectivity) an API which allows the client-side program to call
the DBMS. Today most of the DBMS offers ODBC drivers for
their DBMS. 2 tier architecture provides added security to the
DBMS as it is not exposed to the end user directly.
Example of Two-tier Architecture is a Contact Management
System created using MS- Access.
In the above 2-teir architecture we can see that one server is
connected with clients 1, 2m and 3. This architecture provides
Direct and faster communication.

4. 3-Tier Architecture
3-tier schema is an extension of the 2-tier architecture. 3-tier architecture has following layers
1. Presentation layer (your PC, Tablet, Mobile, etc.)
2. Application layer (server)
3. Database Server
This DBMS architecture contains an Application layer
between the user and the DBMS, which is responsible for
communicating the user's request to the DBMS
system and send the response from the DBMS to the user.
The application layer(business logic layer) also processes functional logic, constraint, and rules
before passing data to the user or down to the DBMS.
Three tier architecture is the mostpopular DBMS architecture.

5. What is Difference between Two-Tier
and Three-Tier Architecture ?
Two-Tier Architecture: The two-tier is based on Client
Server architecture.
The two-tier architecture is like client server application.
The direct communication takes place between
client and server.
There is no intermediate between client
and server. Because of tight coupling a 2 tiered application
will run faster.

6. The above figure shows the architecture of two-tier. Here the direct communication happens
between client and server, there is no intermediate layer between client and server. The
Two-tier architecture is divided into two parts:
1. Client Application (Client Tier)
2. Database (Data Tier)
On client application side the code is written for saving the data in database server. Client
sends the request to server and it process the request & send back with data. The main
problem of two tier architecture is the server cannot respond multiple request same time, as
a result it cause a data integrity issue. When the developers are not disciplined, the display
logic, business logic and database logic are muddled up and/or duplicated in a 2tier client
server system.
Advantages:
1. Easy to maintain and modification is bit easy.
2. Communication is faster.
Disadvantages:
1. In two tier architecture application performance
will be degrade upon increasing the users.
2. Cost-ineffective.

7. Three-Tier Architecture: Three-tier architecture typically comprise a presentation tier,
a business or data access tier, and a data tier. Three layers in the three tier architecture
are as follows:
1. Client layer
2. Business layer
3. Data layer
1.Client layer: Represents Web browser, a Java or
other application, Applet, WAP phone etc. The client tier
makes requests to the Web server who will be serving
the request by either returning static content if it is
present in the Web server or forwards the request to
either Servlet or JSP in the application server for either
static or dynamic content.

8. 2. Business layer: This layer provides the business services. This tier contains
the business logic and the business data. All the business logic like validation of
data, calculations, data insertion etc. Are centralized into this tier as opposed to
2-tier systems where the business logic is scattered between the front end and
the backend. The benefit of having a centralized business tier is that same
business logic can support different types of clients like browser, WAP (Wireless
Application Protocol) client, other standalone applications written in Java, C++, C#
etc. This acts as an interface between Client layer and Data Access Layer. This
layer is also called the intermediary layer helps to make communication faster
between client and data layer.
3. Data layer: This layer is the external resource such as a database, ERP
system, Mainframe system etc. responsible for storing the data. This tier is also
known as Data Tier. Data Access Layer contains methods to connect with
database or other data source and to perform insert, update, delete, get data from
data source based on our input data. Following diagram representing the 3-tier
architecture.

9. Advantages:
• High performance, lightweight persistent objects.
• Scalability – Each tier can scale horizontally.
• Performance – Because the Presentation tier can cache requests, network utilization is
minimized, and the load is reduced on the Application and Data tiers.
• Better Re-usability.
• Improve Data Integrity.
• Improved Security – Client is not direct access to database.
• Forced separation of user interface logic and business logic.
• Business logic sits on small number of centralized machines (may be just one).
• Easy to maintain, to manage, to scale, loosely coupled etc.
Disadvantages:
• Increase Complexity/Effort

10. Thank You