A convenient interface to the database from the web site. A customer does not need to know anything even about the existence of the database, not to mention details of its organization. He/she should be able to get all necessary information by typing in keywords and filling in electronic forms.
Various programming languages (for instance, Java, JavaScript) provide libraries to implement a remote connection to a database server.
A server is a computer that provides a remote access to some service, for instance a web page server "serves" web pages, i.e. sends HTML files, graphics files, etc. in response to http requests, a databse server provides responses to database queries, and so on. One machine can provide several different services at the same time.
A client is a computer that makes a request for a service.
We will use a Java JDBC (Java Database Connectivity) package to facilitate a connection to a relational database. It does not depend on a particular kind of the database, as long as the database supports SQL (Structured Query Language).
SQL is a standard for a query language of a relational database.
An interface has to provide way for customers to fill in forms, press buttons, etc.
We will use javax.swing package to build an interactive graphical interface.