It may be a collection of words, numbers, sounds, images, or video. Databases are usually created using special software that also enables users to search the database in order to retrieve information according to specific criteria. Research databases generally contain references to published information, such as articles that may have been published in a newspaper or magazine. Some research databases also include full text. Each of these classes is then divided and subdivided into more specific disciplines.
Subject dictionaries are another common type.
They are devoted to a specialized field. Many also include brief entries which further describe the person, organization or business. There are two basic types of encyclopedias. A general encyclopedia covers all branches of knowledge and is comprehensive, but general in scope. A subject encyclopedia focuses on a specific discipline or area of knowledge.