A database system that stores data in two-dimensional data tables at the same time such that the program can work with two tables at the same time. It is "relational" if one table defines the relation between entries in rows (data records) and columns (fields). Not all database software claiming to be relational meet the "true" relational database mathematical theory developed by Edgar Codd in 1970. For example, dBASE and FoxPro can link two databases through a common field but are not true relational database programs. One of the most widely selling relational database management systems is the Unix-based system from Oracle Corporation (415-598-8000). Microsoft introduced two very popular systems called Microsoft Access and Visual Fox Pro. Most traditional database packages such as Paradox and dBase also upgraded to relational database systems. See
ODBC. Also see
http://www.trinity.edu/rjensen/260wp/260wp.htm#ODBC.
A language which provides a user interface to relational database management systems, developed by IBM in the 1970s, is called a Structured Query Language (SQL). Development is still underway to enhance SQL into a computationally complete language for the definition and management of persistent, complex objects. This includes user defined data types, support for knowledge based systems, recursive query expressions, and additional database query tools. It also includes the specification of abstract data types (ADTs), object identifiers, methods, inheritance, encapsulation, and all of the other utilities associated with object data management.
For interactive computing on the web, see Distributed Network Computing. Also see See GainMomentum, Database, and 4GL Database Languages..
