database

In computing, a structured collection of data, which may be manipulated to select and sort desired items of information. For example, an accounting system might be built around a database containing details of customers and suppliers. In larger computers, the database makes data available to the various programs that need it, without the need for those programs to be aware of how the data are stored. The term is also sometimes used for simple record-keeping systems, such as mailing lists, in which there are facilities for searching, sorting, and producing records. Examples of database software include Oracle, Sybase, and Microsoft Access.

There are four main types (or ‘models’) of database: relational, object-oriented, hierarchical, and network, of which relational is the most widely used. Object-oriented databases have become more popular for certain types of application, and hybrids like object-relational are also available. In a relational database data are viewed as a collection of linked tables. A free-text database is one that holds the unstructured text of articles or books in a form that permits rapid searching. A telephone directory stored as a database might allow all the people whose names start with the letter B to be selected by one program, and all those living in Chicago by another.