A full-text database incorporates large files of text such as paragraphs from a journal article or chapters from a book. By searching for keywords that might appear in a text, a user can call forth the citation and abstract of the journal article or book. Today, most such databases do not offer the full text for free. Those with full text usually offer the search for citation and abstract for free, but charge for delivery of the full text of an article. A typical database is designed around a central set of facts.
All databases permit their operators to add new information or to update old facts.
In an electronic database stored in a computer, the order of information can be rearranged or sorted quickly. To help people retrieve and print facts, computer databases sort lists into reports. An electronic database can be searched rapidly for specific items of information. Often, the search commands incorporate Boolean algebra logic so users can use AND, OR or NOT to eliminate unwanted entries. One kind of database, known as an expert system, presents information on a specialized field.