DOCUMENT:Q130659  12-AUG-1999  [foxpro]
TITLE   :PRB: "The database must be opened exclusively" Multiuser Error
PRODUCT :Microsoft FoxPro
PROD/VER:3.0
OPER/SYS:
KEYWORDS:kbnetwork kbprogramming

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The information in this article applies to:

 - Microsoft Visual FoxPro for Windows, versions 3.0, 5.0, 5.0a 
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SYMPTOMS
========

In a multiuser situation, when you perform tasks that affect the contents of a
database (.DBC file), the error "The database must be opened exclusively" is
displayed.

CAUSE
=====

The command requires exclusive access to the database. Several commands that
create or modify database objects require that the database not be shared--at
design time or run time.

This error may also occur at run time in an application or EXE if you have
included the database(s) in the project. By including the database(s) in the
project, you have caused them to be read-only, and you will not be able to
properly validate the database. In this situation, it is possible for ISE
CLUSIVE() to return a .T. (true) value and still get the error message described
above.

WORKAROUND
==========

If you receive the error "The database must be opened exclusively" at design
time, all developers must close the database before you can proceed.

To prevent this error from occurring at run time when manipulating views or
connections, create a local database for each user. All users will have
exclusive access to their database, and will also be able to update the table
records contained in a centralized, shared database.

To verify whether or not a database is open exclusively, use the ISEXCLUSIVE()
function. The syntax for the ISEXCLUSIVE() function is:

   ISEXCLUSIVE([cTableAlias | nWorkArea | cDatabaseName [, nType]])

When the nType parameter has a value of 2, the function returns the exclusive
status for a database. The following example code makes sure the database is
open exclusively before using the INDEX ON command:

      CLOSE ALL
      OPEN DATABASE SYS(2004)+"SAMPLES\DATA\TESTDATA"
      SELECT 0
      USE CUSTOMER
      IF ISEXCLUSIVE('testdata',2)
         INDEX ON CITY TAG CITY
         ELSE
         =MESSAGEBOX("Database must be opened Exclusively")
      ENDIF
      CLOSE DATABASE

NOTE: The above code uses CLOSE ALL to close all the files so that the database
can be opened but not selected, making the CLOSE DATABASE command useless. Of
course using CLOSE DATABASE ALL might not be helpful if only one database needs
to be closed. Therefore, issue the following code to select a certain database
to close and reopen:

      SET DATABASE TO <dbc name>
      CLOSE DATABASE
      OPEN DATABASE <dbc name> EXCLUSIVE

This ensures that the correct database container is selected, closed, and
reopened.


STATUS
======

This behavior is by design.

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

If a view or a table contained in a database is open for shared use, the
database is also shared. Therefore, all multiuser applications require that a
database be shared.

However, commands that directly relate to the database (.DBC file) structure and
commands that involve the creation or deletion of objects require exclusive use
of the database. These commands include:

   CREATE TABLE
   MODIFY STRUCTURE
   ALTER TABLE
   ADD TABLE
   RENAME TABLE

   CREATE SQL VIEW
   MODIFY VIEW
   DELETE VIEW
   RENAME VIEW

   CREATE CONNECTION
   MODIFY CONNECTION
   DELETE CONNECTION
   RENAME CONNECTION

   INDEX ON && You can however use INDEX ON on a view
   DELETE TAG

   CREATE TRIGGER
   DELETE TRIGGER

   APPEND PROCEDURES
   COPY PROCEDURES
   MODIFY PROCEDURE

   COMPILE DATABASE
   PACK DATABASE
   VALIDATE DATABASE

Additional query words: denied

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Keywords          : kbnetwork kbprogramming 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP500 kbVFP500a
Version           : 3.0
Issue type        : kbprb

=============================================================================

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