1.2.4 Database Server

A CGI program does not need to interact with a database server. In fact, one can write useful CGI scripts without using a database. However, for eCommerce and data cataloging/storing/retrieval web sites, most CGI scripts need to access some database server.

A database server is a program that maintains databases. A database is essentially a group of tables. In a table, a row is a record, while a column is the values of the same field of all the records. We'll discuss databases more later on.

Examples of database servers include MySQL (GPLed), PostgresQL (GPLed), Oracle (proprietary), SQL Server (Microsoft Proprietary) and DB2 (IBM proprietary). Fortunately, most of these database servers comply to the SQL standard, which makes it somewhat easy to port CGI programs from one database to another. There are also CGI libraries that help to abstract low-level details and differences of these different databases so that CGI scripts can be fairly independent of the database server.