Database in the broadest sense of the word is a collection of various types of data including reports, tables etc. In order to manage these sets of information and support activities that use them, multiple database management systems (or DBMS) were created. Among the most popular ones we can name Oracle, Microsoft SQL, MySQL, and many other. These systems allow users to access many databases at once as well as administer, retrieve, and update information contained therein.
Database management systems may be general-purpose and special-purpose. In the first case, software tends to try to meet as many needs of the user as possible. However, some systems do not require such complexity and only need some functions instead of a whole pack, e.g. a system that handles emails.
Different types of DBMS are widely used for administrative purposes in companies and enterprises. A bit more specialized systems are required to be used in order to process economic models or information on engineering.
Textbooks on database range from basic concepts and fundamentals necessary for understanding to programming using different software applications as well as SQL, which is the most popular programming language used in DBMS.