Q175966: BUG: SQL_PRESERVE_CURSORS Fails on Reuse of a Connection Handle

Article: Q175966
Product(s): Open Database Connectivity (ODBC)
Version(s): 3.0,6.5
Operating System(s): 
Keyword(s): kbcode kbProgramming kbSQLServ650bug
Last Modified: 22-FEB-2002

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The information in this article applies to:

- Microsoft SQL Server version 6.5 
- Microsoft Open Database Connectivity, version 3.0 
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BUG #: 17471 (6.50)

SYMPTOMS
========

If you reuse a previously used connection handle and attempt to preserve cursors
over transaction boundaries (that is, if the SQL Server driver connect option
SQL_PRESERVE_CURSORS is used), the following error occurs:

  [Microsoft][ODBC Driver Manager] Function sequence error

WORKAROUND
==========

To work around this problem, do not reuse connection handles if you need to
preserve cursors. Instead, close the handle and reopen a new one for preserve
cursor operations.

STATUS
======

Microsoft has confirmed this to be a problem in SQL Server version 6.5 and Open
Database Connectivity version 3.0. We are researching this problem and will post
new information here in the Microsoft Knowledge Base as it becomes available.


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

The following script, used with ODBC Test (Odbcte32.exe) demonstrates the
problem:

     1)   Full Connect:  (connect to Pubs).
     2)   SQLDisconnect:
     3)   SQLSetConnectOption:
           fOption=Conn: SQL_ODBC_CURSORS=110,
           vParam=SQL_CUR_USE_DRIVER=2
     4)   SQLDriverConnect: (reconnect to Pubs)
     5)   SQLSetConnectOption:
           fOption=Conn: SQL_AUTOCOMMIT=102,
           vParam=SQL_AUTOCOMMIT_OFF=0
     6)   SQLAllocStmt:
     7)   SQLSetStmtOption:
           fOption=SQL_CURSOR_TYPE=6,
           vParam=SQL_CURSOR_STATIC=3
     8)   SQLSetConnectOption:
           fOption=1204 (#def value for SQL_PRESERVE_CURSORS)
           vParam=1 (#def value for SQL_PC_ON)
     9)   SQLPrepare:
           select emp_id, fname from employee where job_id = 13
     10)   SQLExecute:
     11)   SQLTransact:
     12)   Bind Col All:
     13)   SQLSetStmtOption:
           fOption=SQL_ROWSET_SIZE=9,
           vParam=20,
     14)   SQLExtendedFetch:
           fFetchType=SQL_FETCH_NEXT=1
           irow=0, pcrow=VALID, rgfRowStatus=VALID
        Return:   SQL_ERROR=-1
        szSqlState = "S1010", *pfNativeError = 0, *pcbErrorMsg = 56
        szErrorMsg="[Microsoft][ODBC Driver Manager] Function sequence error"

The script above will run successfully if you do either of the following:

- Do not disconnect.

  -or-

- Free the connection handle and allocate a new one.

Additional query words:

======================================================================
Keywords          : kbcode kbProgramming kbSQLServ650bug 
Technology        : kbSQLServSearch kbAudDeveloper kbSQLServ650 kbODBCSearch kbODBC300
Version           : :3.0,6.5
Issue type        : kbbug

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