PRB: "The database must be opened exclusively" Multiuser Error

ID: Q130659

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 3.0, 5.0, 5.0a

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

Keywords : kbnetwork kbprg FxprgMultiuser
Version : 3.0
Platform : WINDOWS
Issue type : kbprb