Because of their speed and accuracy, computers have traditionally been utilized for commercial application development. Commercial applications typically have many, distinct levels, resulting in a multi-tier distributed computing approach. This concept is entirely based on the client/server computer paradigm.
Client: A client is a computer that end-users use to run applications that are linked to a network in order to use the services provided by servers such as a database server, file server, or web server. As a result, a client will only run user programs and communicate with servers for data and file services. End users enter data and interact with the business application, which is run by clients.
Server: A server is a computer system that is connected to the internet and delivers services to other computers on the network. File servers, application servers, database servers, e-mail gateways, and communication servers are all examples of servers. These computers run Novell NetWare, Windows NT, or UNIX OS, which are network operating systems.
Client-Server Architecture aka Two-Tier Architecture:
The client/server computing model is one in which data is captured and validated on a computer known as a client, and validated data (captured by the client) is saved on another computer known as a server.
Please read the full article on Two-Tier architecture here.
In this article, we will be discussing Three-Tier / Multi-Tier Architecture.
In a three-tier client/server approach, business or transaction rules are implemented in an application server that sits between the client and the database server, leaving the client to handle the user interface and the database server to handle the database. This allows business or transaction rule changes to be made only on the application server. In corporate/business applications, a three-tiered client/server design is common. This improves the application’s scalability.
Three-tier applications :
Client tier / Presentation tier: A local computer on which a web browser displays a web page that can display and edit data from a remote data source, or a stand-alone built Front-end application (in non-web-based applications).
Middle tier / Logic tier: A server computer that hosts components that encapsulate an organization’s business rules is known as the middle tier. Active server page scripts executed on an internet information server or generated executables (in non-web-based applications) are examples of middle-tier components.
Data-tier / Data source tier: A computer that hosts a database management system (DBMS), such as Microsoft SQL or MySQL or Oracle server databases, is known as the data source tier.