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Q131031: READ NOLOCK Behavior in Visual FoxPro

Article: Q131031
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 15-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
=======

The behavior of the READ NOLOCK command in Visual FoxPro is slightly different
from its behavior in FoxPro version 2.x.

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

READ NOLOCK alters the behavior of the READ command, so records are not
automatically locked by the READ.

In FoxPro version 2.x, issuing a READ NOLOCK command automatically disables all
fields. Attempts to key data into the fields causes a high-pitched beep until a
SHOW GETS LOCK command is issued.

In Visual FoxPro, the beep is no longer heard. Instead, a "Record is read only"
message appears on the status bar. A SHOW GETS LOCK command is still required to
edit the fields.

If buffering is enabled, the READ NOLOCK command overrides the locking behavior
of the buffering mode that is in effect. If pessimistic locking is enabled, the
record is not locked until the SHOW GETS LOCK command is issued. If optimistic
locking is enabled, the record is locked at the time the SHOW GETS LOCK is
issued, not at the time the record is written to disk.

The TABLEUPDATE() and TABLEREVERT() commands should not be used in conjunction
with READ NOLOCK. You should modify the application to use buffering completely
or to use READ NOLOCK without enabling buffering.

Additional query words: VFoxWin

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

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