You should be aware what is a program. What all are the key factors in a program...
So first lets start with the Basics.....
We all are creating Applications. So lets check what all are the functions performed by an Application.
The functions performed by an application can be divided into three categories
- User services
- Business services and
- Data Services
User Services layer constitutes the front end of the solution. It is also called the Presentation Layer because it provides the interactive user interface.
The business services layer controls the enforcement of business rules on the data of an organization.
Business rules encompass those practices and activities that define the behavior of an organization.
The data services layer comprises of the data and the functions for manipulating this data.
TYPES OF APPLICATIONS
Applications may vary from Single-tier desktop applications to multi-tier applications (two, three or n-tier architecture).
SINGLE-TIER Architecture
In a single-tier architecture a single executable file handles all functions relating to the user, business and data service layers. Such an Application is also called Monolithic applications.
TWO-TIER Architecture
The tow-tier architecture divides an application into two components:-
Client - Implements the user interface
Server - Stores Data
In case for this architecture the user and data services are located separately either on same machine or in separate machine.
THREE-TIER Architecture
In case of Three-Tier architecture all the three service layers reside Separately, either on the same machine or on different machine. The user interface interacts with the Business logic. Business logic validates the data sent by the interfaces and forwards it to the database if it confirms to the requirement.
n-TIER Architecture
An n-tier application uses business objects for handling business rules and data access. It has multiple servers handling business services. This application architecture provides various advantages over other types of application architectures. The advantages include extensibility, resilience to change, maintainability and scalability of the application.
.png)
