What is a database? As you probably know, a database is an organized collection of data used for the purpose of modeling some type of organization or organizational process. It really doesn't matter whether you're using paper or a computer software program to collect and store the data. As long as you're gathering data in some organized manner for a specific purpose, you've got a database. Throughout the remainder of this discussion, we'll assume that you're using a computer software program to collect and maintain your data.
There are two types of databases found in database management, operational databases and analytical databases.
Operational databases are the backbone of many companies, organizations, and institutions throughout the world today. This type of database is primarily used in on-line transaction processing (OLTP) scenarios, that is, in situations where there is a need to collect, modify, and maintain data on a daily basis. The type of data stored in an operational database is dynamic, meaning that it changes constantly and always reflects up-to-the-minute information. Organizations, such as retail stores, manufacturing companies, hospitals and clinics, and publishing houses, use operational databases because their data is in a constant state of flux.
In contrast, analytical databases are primarily used in on-line analytical processing (OLAP) scenarios, where there is a need to store and track historical and time-dependent data. An analytical database is a valuable asset when there is a need to track trends, view statistical data over a long period of time, and make tactical or strategic business projections. This type of database stores static data, meaning that the data is never (or very rarely) modified. The information gleaned from an analytical database reflects a point-in-time snapshot of the data. Chemical labs, geological companies, and marketing-analysis firms are examples of organizations that use analytical databases.
Analytical databases often use data from operational databases as their main data source, so there can be some amount of association between them; nevertheless, operational and analytical databases fulfill very specific types of data-processing needs, and creating their structures requires radically different design methodologies. This book focuses on designing an operational database because it is still the most widely used type of database in the world today.