visual foxpro

Visual FoxPro is a data-centric object-oriented and procedural programming language produced by Microsoft. It is derived from FoxPro (originally known as FoxBASE) which was developed by Fox Technologies beginning in 1984. Fox Technologies merged with Microsoft in 1992 and the software acquired further features and the prefix "Visual". The last version of FoxPro (2.6) worked under Mac OS, DOS, Windows, and Unix: Visual FoxPro 3.0, the first "Visual" version, dropped the platform support to only Mac and Windows, and later versions were Windows-only. The current version of Visual FoxPro is COM-based and Microsoft has stated that they do not intend to create a Microsoft .NET version.

FoxPro is a member of the class of languages commonly referred to as "xBase" languages, which have syntax based on the dBase programming language. Other members of the xBase language family include Clipper and Recital. (A history of the early years of xBase can be found in the dBASE entry.)

Visual FoxPro, commonly abbreviated as VFP, is typically viewed by the general public as being merely a Database Management System (DBMS). This ignores the fact that it includes not only a DBMS engine, but also a full-featured Programming Language. It can be used to write not just traditional fat client applications, but also middleware and web applications.

In late 2002, some community members demonstrated that Visual FoxPro can run on Linux under the Windows emulator Wine. In 2003, this led to complaints by Microsoft: it was claimed that the deployment of runtime FoxPro code on non-Windows machines violates the End User License Agreement.^[1]

Rumors suggesting that Microsoft intends to end support for FoxPro have been common since Microsoft's acquisition of the product, despite the product having one of the longest support timeframes for a Microsoft product (extended support until 2015). VFP 9 was released to manufacturing on December 17, 2004, and the Fox team is currently working on a project codenamed Sedna which will be built on top of the VFP9 codebase and consist mainly of Xbase components that support a number of interoperability scenarios with various Microsoft technologies including SQL Server 2005, .NET, WinFX, Windows Vista, and Office 12. The development of Version 9 is ongoing with a service pack that was released December 8, 2005.

On March 1, 2006, Microsoft released a Community Technology Preview (CTP) of Sedna. According to the Fox team, the current plan "for releasing Service Pack 2 for VFP 9.0 will be some time in 2007, at the same time or near the same time of the release of Sedna". The latest CTP was released on October 13, 2006 by Microsoft.

In December 2005, VFP broke into the top 20 on TIOBE's Programming Community Index for the first time. As of October 2006 it is at position 20, making it a "B" language.

Version information

Operating system compatibility

Information on Executable Files

Code samples

Object

loForm = CREATEOBJECT("HiForm")
loForm. Show(1)

DEFINE CLASS HiForm AS Form
  AutoCenter = .T.
  Caption = "Hello, World"

  ADD OBJECT lblHi as Label WITH ;
    Caption = "Hello, World!"
ENDDEFINE

loMine = CREATEOBJECT("MyClass")
? loMine.cProp1   && This will work.
? loMine.cProp2   && Program Error: Property CPROP2 is not found.

? loMine. MyMethod1()  && This will work.
? loMine. MyMethod2()  && Program Error: Property MYMETHOD2 is not found.

DEFINE CLASS MyClass AS Custom
  cProp1 = "My Property"    && This is a public property
  HIDDEN cProp2     && This is a private (hidden) property

  PROCEDURE Init()    && Class constructor
    This.cProp2 = "This is a hidden property."
  ENDPROC

  PROCEDURE MyMethod1()   && This is a public method
    RETURN This. MyMethod2()
  ENDPROC

  HIDDEN PROCEDURE MyMethod2()  && This is a private (hidden) method
    RETURN This.cProp2
  ENDPROC
ENDDEFINE

Data handling

* Create a table
CREATE TABLE randData (iData I)

* Populate with random data using xBase and SQL DML commands
FOR i = 1 TO 50
        APPEND BLANK
        REPLACE iData WITH (RAND() * 100)

  INSERT INTO randData (iData) VALUES (RAND() * 100)
ENDFOR

* Place a structural index on the data
INDEX ON iData TAG iData
CLOSE ALL

* Display sorted data using xBase-style commands
USE randData
SET ORDER TO iData
GO TOP
LIST NEXT 10  && First 10 (end-of-line comment)
SKIP 81
LIST NEXT 10  && Last 10
CLOSE ALL

* Browse sorted data using SQL DML commands
SELECT * ;
  FROM randData ;
  ORDER BY iData DESCENDING

ODBC Access using SQL Passthrough

* Connect to an ODBC data source
LOCAL nHnd
nHnd = SQLCONNECT ("ODBCDSN", "user", "pwd")

* Execue a SQL command
LOCAL nResult
nResult = SQLEXEC (nHnd, "USE master")
IF nResult < 0
  MESSAGEBOX ("MASTER database does not exist!")
ENDIF

* Retrieve data from the remote server and stores it in
* a local data cursor
nResult = SQLEXEC (nHnd, "SELECT * FROM authors", "QAUTHORS")

* Update a record in a remote table using parameters
LOCAL cAuthorID, cAuthorName
cAuthorID = "1001"
cAuthorName = "New name"
nResult = SQLEXEC (nHnd,"UPDATE authors SET auth_name = ?cAuthorName WHERE auth_id = ?cAuthorID")

* Close the connection
SQLDISCONNECT(nHnd)

For another sample, see the Visual FoxPro implementation of the Levenshtein Distance algorithm.

Beta code names

• VFP 3 - Taz
• VFP 5 - RoadRunner
• VFP 6 - Tahoe
• VFP 7 - Sedona
• VFP 8 - Toledo
• VFP 9 - Europa
• VFP Next - Sedna