A database is a collection of information that is organized so that it can easily
be accessed, managed, and updated. In one view, databases can be classified according
to types of content: bibliographic, full-text, numeric, and images.
In computing, databases are sometimes classified according to their organizational
approach. The most prevalent approach is the relational database, a tabular database
in which data is defined so that it can be reorganized and accessed in a number
of different ways. A distributed database is one that can be dispersed or replicated
among different points in a network. An object-oriented programming database is
one that is congruent with the data defined in object classes and subclasses.
Computer databases typically contain aggregations of data records or files, such
as sales transactions, product catalogs and inventories, and customer profiles.
Typically, a database manager provides users the capabilities of controlling read/write
access, specifying report generation, and analyzing usage. Databases and database
managers are prevalent in large mainframe systems, but are also present in smaller
distributed workstation and mid-range systems such as the AS/400 and on personal
computers. SQL (Structured Query Language) is a standard language for making interactive
queries from and updating a database such as IBM's DB2, Microsoft's SQL Server,
and database products from Oracle, Sybase, and Computer Associates.