PRB: CDBVariant Contains Wrong BOOL Value When Calling CRecordset::GetFieldValue()

• Microsoft Visual C++, 32-bit Editions, version 6.0

SYMPTOMS

When calling the CRecordset::GetFieldValue() method that accepts a CDBVariant object as a parameter and the target field in the database is a bit field, the BOOL value (m_boolVal) is incorrect.

RESOLUTION

Use an explicit type other then SQL_C_BIT, such as SQL_C_UTINYINT or SQL_C_SLONG, as the type of variable to bind to.

Please see the More Information for details.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

The following steps use the SQL Server Pubs database as an example:

Steps to Reproduce Behavior

1. Create an MFC Single Document Interface project with database header file support.



2. Create a menu item or button event handler.



3. Type the following code in the handler and change the connect string to reflect your SQL Server database:

   
   	CDatabase db;
   	db.OpenEx(_T("Driver=SQL Server;Server=(local);Database=Pubs;UID=sa;PWD=;"));
   
   	CRecordset rs;
   	rs.m_pDatabase = &db;
   	rs.Open(CRecordset::forwardOnly, _T("SELECT * FROM authors"));
   
   	CDBVariant varField;
   	rs.GetFieldValue(_T("contract"),varField);
   	BOOL boolValue = varField.m_boolVal;
    




4. Observe the value of boolValue. It will be incorrect.

Workaround

	rs.GetFieldValue(_T("contract"),varField,SQL_C_UTINYINT);
	BYTE byteValue = varField.m_chVal; 

	rs.GetFieldValue(_T("contract"),varField,SQL_C_SLONG);
	BOOL boolValue = varField.m_boolVal; 

Additional query words: boolean odbc

Keywords : kbDatabase kbMFC kbODBC kbVC kbVC600 kbGrpVCDB
Version : winnt:6.0
Platform : winnt
Issue type : kbprb