Slide 1.4: A generic structure of a database-driven web system

Slide 1.3: A generic structure of a file-driven web system
Slide 1.5: Guidelines of programming exercises
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A Generic Structure of a Database-Driven Web System

A database-driven web site is often implemented with a three-tiered client-server architecture, which consists of three layers:

User interface: It runs on a desktop PC or workstation (the client) and uses a standard graphical user interface. The main function of this tier is to translate tasks and results to something the user can understand.

Functional module: This tier coordinates the application, processes commands, makes logical decisions and evaluations, and performs calculations. It also relays data between the two surrounding tiers.

Database management system (DBMS): A DBMS on a host computer stores and manages the data required by the middle tier for further processing. The middle tier then sends the processed data back to user.

The three-tier design has many advantages over traditional two-tier or single-tier designs, the chief one being:

The added modularity makes it easier to modify or replace one tier without affecting the other tiers.

^†SQL (Structured Query Language), which is a standard interactive language for getting information from and updating a database. For example, the SELECT statement is used to retrieve data from a database.