E commerce application architecture

E-commerce is based on the client-server architecture in which the client can be an application, which uses a Graphical User Interface (GUI) that sends request to a server for certain services and the server is the provider of the services requested by the client. The E - Commerce Web server is the computer program that provides services to "other computer programs and serves requested Hyper Text Mark-up Language (HTML) pages or files.

A client refers to a customer who requests for certain services and the server refers to the business application through which the services are provided. A machine can be both a client as well as a server. There are two types of client server architecture that E-commerce follows including two-tier and three-tier architectures. In two-tier client-server architecture the user interface runs on the client. The database is stored on the server. The business application logic can either run on the client or the server and likewise the user application logic can either run on the client or the server. It allows the client processes to run separately from the server processes such as on different computers. The three-tier architecture emerged to overcome the limitations of the two-tier architecture.

In three-tier architecture, the user interface and the business application logic known as business rules. The data storage and access, are developed and maintained as independent modules.  The three-tier architecture includes three tiers named as top tier, middle tier and third tier. The top tier includes a user interface where user services such as session, text input, and dialog and display management reside and the middle tier provides process management services such as process development, process monitoring and process resourcing that are shared by the multiple applications.

The third tier provides database management functionality in which the data management component ensures that the data is consistent throughout the distributed environment. Also the centralized process logic in this architecture, which makes administration easier by localizing the system functionality, is placed on the middle tier. The client-server architecture provides standardized and abstract interfaces to establish communication between multiple modules. When these modules are combined, they become an integrated business application and here the each module is a shareable and reusable object that can be included in another business application.

The functions of a business application are isolated within the smaller business application objects and so application logic can be modified easily here. In the client-server architecture, each business application object works with its own encapsulated data structures that correspond to a specific database and so on. When business application objects communicate, they send the data parameters as specified in the abstract interface rather than the entire database records, these is the process to be take place. This also reduces the network traffic. In the client-server architecture, a programmer can develop presentation components. They do these without knowing the business application logic. For more