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Q127795: INF Back-Link Functionality in Visual FoxPro for Windows

Article: Q127795
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0
Operating System(s): 
Keyword(s): 
Last Modified: 12-FEB-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
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SUMMARY
=======

This article describes how back-links are implemented in Visual FoxPro tables
and how to use your Visual FoxPro tables with previous versions of FoxPro.

MORE INFORMATION
================

A Visual FoxPro table (.DBF) that is stored in a database (DBC) holds a
reference to the database that contains it. This information is referred to as
back-link. A back-link allows opening or selecting a table in a database without
explicitly referring to the DBC. It provides a way to access the rules and
triggers associated with a table.

Back-link information is recorded in the .DBF header and contains the relative
path and file name that link the table to the database.


Two hundred and sixty three bytes (263) have been added to the .DBF header to
accommodate back-link functionality. Any table created with Visual FoxPro will
have to be modified to be used with FoxPro versions 2.x for Windows, FoxPro
versions 2.x for MS-DOS, or FoxBASE+.

You can convert a Visual FoxPro table to the FoxPro version 2.x structure by
using the COPY TO command. For example:

     USE SAMPLES\DATA\CUSTOMER
     COPY TO CUSTBAK1 TYPE FOX2x && Copies to a FoxPro 2.x compatible format
     COPY TO CUSTBAK2 TYPE FOXPLUS && Copies to a FoxBASE+ compatible format

A FoxPro version 2.x for Windows or FoxPro version 2.x for MS-DOS table is
converted to the Visual FoxPro format when it is added to a database, or when
its structure is changed to use NULLs or a data type introduced in Visual
FoxPro. When the conversion occurs, a backup (.BAK) file is created.

Additional query words: VfoxWin

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300
Version           : WINDOWS:3.0

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