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Q110968: INFO: FoxPro Header Check to Determine if Table is Corrupt

Article: Q110968
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:2.5b; MS-DOS:2.5,2.5a,2.5b,2.6; WINDOWS:2.5,2.5a,2.5b,2.6,3.0
Operating System(s): 
Keyword(s): kbHWMAC kbvfp kbvfp300 kbDSupport
Last Modified: 03-AUG-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
- Microsoft FoxPro for Windows, versions 2.5, 2.5a, 2.5b, 2.6 
- Microsoft FoxPro for MS-DOS, versions 2.5, 2.5a, 2.5b, 2.6 
- Microsoft FoxPro for Macintosh, version 2.5b 
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SUMMARY
=======

When opening a database file (.DBF), FoxPro checks the header for the following
five conditions that indicate corruption in a table:

1. Is the record length invalid?

   - Record length <= 1

   - Record length > maximum record length

2. Are there no fields?

3. Are there more fields than permitted?

4. Is the number of records < 0?

5. Is the file size invalid?

   - (Start-of-data + the # of records) * rec. length > file size

NOTE: Start-of-data is where the first byte of the first record begins.

Additional query words:

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Keywords          : kbHWMAC kbvfp kbvfp300 kbDSupport 
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbFoxproSearch kbZNotKeyword3 kbFoxPro250bMac kbFoxPro250DOS kbFoxPro250aDOS kbFoxPro250bDOS kbFoxPro260DOS kbFoxPro260 kbFoxPro250 kbFoxPro250a kbFoxPro250b kbVFP300
Version           : MACINTOSH:2.5b; MS-DOS:2.5,2.5a,2.5b,2.6; WINDOWS:2.5,2.5a,2.5b,2.6,3.0
Issue type        : kbinfo

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