'''Visual DataFlex''' is a [[4GL]] windows [[programming language]] by [[Data Access (company)|Data Access]], targeted at creating [[database]] and client-server type programs.
== Architecture ==
Visual DataFlex has a 3-layer architecture:
;Bottom layer: Tables at this level represent customer information. Data dictionaries for each table define the rules for saving, editing, deleting, or finding a customer.
;Middle layer: Tables at this level represent orders to customers. A ''Data Dictionary Connectivity Object Tree'' defines how tables relate to each other, and ensures that all business rules of the connected tables are in force and validate.
;Top layer: A graphical user interface ([[GUI]]) that allows users to enter, find, create, modify, or delete data.
== History ==
{{cleanup|section|date=February 2008}}
Data Access Worldwide of Miami, USA is the company behind the studio and language and built its business up around the console mode [[DataFlex]] language which was released prior to [[MS-DOS|DOS]] and competed with [[dBase|dBase II]] in early microcomputer technology. The first attempt at a windows product was ''DataFlex for Windows'' which failed as it was a sort of windows bolted on top of DOS product. Then they released Visual DataFlex 4.0 in 1997 which allowed users to write native 32 bits Windows applications. Every 6 months a new revision level is released. Visual DataFlex is now in revision 16, named VDF 2010<ref>[http://www.visual-dataflex.co.uk/Include/ElectosFileStreaming.asp?FileId=861 Visual DataFlex 2009/15.0 – Overview]</ref>, and features a datadictionary layer of business rules which is of dual use with the windows product and the webapp extension.
== References ==
<references />
== External links ==
* [http://www.visualdataflex.com Official website]
* [http://www.vdfwiki.com vdfwiki.com]
* [http://support.dataaccess.com/forums/ Support forum]
* [http://www.vdf-guidance.com Visual DataFlex open source website]
