Q194678: HOWTO: SQL Server Identity, OLE DB Templates and OLE DB for ODBC

Article: Q194678
Product(s): Microsoft C Compiler
Version(s): WINDOWS:2.5; winnt:6.0
Operating System(s): 
Keyword(s): kbDatabase kbODBC kbProvider kbVC600 kbATL300 kbConsumer kbGrpDSVCDB kbDSupport kbMDAC2
Last Modified: 07-MAY-2001

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
- Microsoft Data Access Components version 2.5 
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SUMMARY
=======

When using the OLE DB Templates with a SQL Server database, it is often
necessary to add records to a table that contains an identity column.

Getting an identity column to increment properly with the OLE DB for ODBC
provider that ships with Visual C++ 6.0, Msdasql.dll, requires that the
COLUMN_ENTRY_STATUS macro be used.

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

The following sample code demonstrates how to use this macro when defining an
accessor map with Visual C++ 6.0 OLE DB Consumer Templates:

Sample Code
-----------

     class CMyTableAccessor
     {
     public:
        LONG m_id;          // This is an identity column
        DWORD m_id_status;  // Status variable for id column
        TCHAR m_name[11];

     BEGIN_COLUMN_MAP(CMyTableAccessor)
       COLUMN_ENTRY_STATUS(1, m_id, m_id_status)
       COLUMN_ENTRY(2, m_name)
     END_COLUMN_MAP()

     ...
     };

The code to add a new record to the table would resemble the following:

     CMyTable rs;

     rs.Open();
     rs.ClearRecord();  //Null out current structure

     strcpy(rs.m_name , "New Name");
     rs.m_id_status = DBSTATUS_S_IGNORE;  //Tells the provider to ignore this
                                          // column when updating.

     rs.Insert();  // Insert new record into the table letting server update
                  // of the identity column.
     rs.Close();

REFERENCES
==========

Please see the following topics in MSDN online documentation:

- VC++ documentation for COLUMN_ENTRY_STATUS

- OLE DB Topic titled "Status" defines "DBSTATUS_S_IGNORE"

Additional query words:

======================================================================
Keywords          : kbDatabase kbODBC kbProvider kbVC600 kbATL300 kbConsumer kbGrpDSVCDB kbDSupport kbMDAC250 
Technology        : kbVCsearch kbAudDeveloper kbMDACSearch kbMDAC250 kbVC600 kbVC32bitSearch
Version           : WINDOWS:2.5; winnt:6.0
Issue type        : kbhowto

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