Information Technology Workbook

4   Databases
You may think that any collection of information is a "database." But in the more specific language of information technology a database is a special arrangement of data that makes it readily accessible. The best database mechanisms are those that provide rapid, flexible access to data even in ways that had not been entirely anticipated by the database designers.

A database is usually built relying on support software known as a database management system (DBMS). Three generations of database management system have been invented since computers began to be used commercially. Hierarchical databases such as IBM's IMS system were limited in the types of data structures they could support. IMS was widely used on mainframe computers. Network databases were prominent in the 1970s-80s and were more capable than IMS but were also limited in flexibility. Modern databases are based on relational data concepts. Relational databases rely on data arranged in tables accessed by Structured Query Language (SQL). Relational databases free database designers and users from concerns over how data is physically stored. MySQL, SQL Server, DB2, and Oracle are modern relational database management systems.

Copyright 2006 Jim Janossy and Laura McFall                                           Click here or scroll down for web and podcast links

4.1   Introduction to database technology

4.2   An example and tutorial on modern web usage of a database

4.3   Database design and entity/relationship diagramming

4.4   Data mining and ethical issues of privacy

Click here to return to the top of Chapter 4