DBASE programming language

A language that is tightly integrated into a quasi-relational desktop database system. It's database system was one of the first to provide a "header" section for describing the structure of the data. This meant that the program no longer required advance knowledge of the data structure, but rather could ask the data file how it was structured. Thus was born the dBF file. It started as a hobby project to track sports statistics at the Jet Propulsion Laboratory, and was later sold to a company called Ashton Tate to became a very popular microcomputer custom business application programming environment in the 1980's. The language spawned several dialects, including Clipper, Visual FoxPro, QuickSilver, Visual Objects and others, collectively referred to as the xBase family. However, the language publisher was slow to adapt to new technologies such as SQL (structured query language) and GUI (graphical user interface using a mouse, icons, windows, etc.). Microsoft's promotion of its Access product also ate into dBase sales. Others, such as FoxPro, Clipper and Visual Object were not quite so slow to adapt. Critics of the language point to its "modal" nature, meaning that how a given statement acts depends heavily on it's environment's settings. However, used in an event-driven environment, modal scope is less of a problem. Its modal nature also keeps it compact in many cases because one does not have to keep supplying context, handles, or paths to each and every statement in a related group. Many feel it still makes a good ad-hoc data conversion and analysis tool because unlike SQL, one can easily view and save intermediate steps.

Example

The following example opens an employee table ("empl"), sets a "filter" to view only managers (those who supervise one or more employees), gives every manager a 10-percent raise, displays the result in a tabular grid, turns off the filter (to show all employees, not just managers), and then prints the names and salaries of all employees to a printer. (Filters trump the "all" scope.)

 use empl            \n  set filter to supervises > 0\n  replace all salary with salary * 1.1\n  browse\n  set filter to\n  list all fname, lname, salary to print

dBase was also one of the first languages to implement string evaluation (long before Perl)

 i = 0\n  macro = "i + 10"\n  i = ¯o\n  // i now has the value 10

See dBase for developmental history of the language.

Links

• Current dBASE home: http://www.dbase.com\n* Current FoxPro home: http://msdn.microsoft.com/vfoxpro/\n[[Category:XBase languages