DOCUMENT:Q114630  11-MAR-2000  [odbc]
TITLE   :PRB: ODBC SQL Server Driver and Access Violation on SQL Server
PRODUCT :Open Database Connectivity (ODBC)
PROD/VER:WINDOWS:1.0
OPER/SYS:
KEYWORDS:

======================================================================
1.01.2807

WINDOWS

kbusage

-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Open Database Connectivity, version 1.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When using the SQL Server ODBC driver with an ODBC enabled application to access
SQL Server for Windows NT, an update on a table with a trigger which calls a
stored procedure, which in turn contains an unmatched COMMIT TRAN or ROLLBACK
TRAN statement, may cause an access violation to be encountered on SQL Server,
causing SQL server to terminate.

In case of Access and Visual Basic, an attempt to update the SQL server table,
will generate the following message,

   ODBC - Update failed.

followed by:

   [Microsoft][ODBC SQL Server Driver]Communication Link Failure.

For ODBC application writer, the following steps will encounter the behavior:

      // prepared execution to update the table
      SQLPrepare: update <tablename> set <col>= ? where <col>=?

      //Set parameters for the above prepared stmt
      SQLSetParam:

      //Begin transaction
      SQLSetConnectOption:
         fOption: SQL_AUTOCOMMIT
         vParam : FALSE or 0

      //Execute the previously prepared stmt
      SQLExecute:

This will return

   SQL_ERROR, with szSqlState = "08S01", *pfNativeError = 0, *pcbErrorMsg = 61,
   szErrorMsg = [Microsoft][ODBC SQL Server Driver] Communication link failure.

WORKAROUND
==========

This does not happen, if on SQL Server, the ROLLBACK TRAN or COMMIT TRAN
statement itself is contained in the trigger instead of being in the stored
procedure that is called by the trigger.

This happens only for prepared execution in ODBC. Thus, another workaround is to
revoke stored procedure permissions from the users which will result in a
non-prepared execution, and it will not cause access violation on the SQL
Server.

Additional query words: 1.01.2807

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbODBCSearch kbODBC100
Version           : WINDOWS:1.0
Issue type        : kbprb

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2000.