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Rowset Creation Example

The code in this example shows how to create a rowset.

// myCreateRowset
//   This function creates an OLE DB Rowset object from the given
//   provider's Session object. It first obtains a default table
//   name from the user through the tables schema rowset, if
//   supported, then creates a Rowset object by one of two methods:
//   - If the user requested that the Rowset object be created
//     from a Command object, it creates a Command object, then
//     obtains command text from the user, sets properties and
//     the command text, and finally executes the command to
//     create the Rowset object
//   - Otherwise, the function obtains a table name from the user
//     and calls IOpenRowset::OpenRowset to create a Rowset object
//     over that table that supports the requested properties
HRESULT   myCreateRowset
   IUnknown *            pUnkSession,
   IUnknown **            ppUnkRowset
   HRESULT               hr;
   IUnknown *            pUnkCommand                     = NULL;
   IOpenRowset *         pIOpenRowset                    = NULL;
   WCHAR                 wszTableName[MAX_NAME_LEN + 1]  = {0};

   const ULONG           cProperties                  = 2;
   DBPROP                rgProperties[cProperties];
   DBPROPSET             rgPropSets[1];

   // Obtain a default table name from the user by displaying the
   // tables schema rowset if schema rowsets are supported.
   CHECK_HR(hr = myCreateSchemaRowset(DBSCHEMA_TABLES, pUnkSession, 
      MAX_NAME_LEN, wszTableName));

   // Set properties on the rowset, to request additional functionality
   myAddRowsetProperties(rgPropSets, cProperties, rgProperties);

   // If the user requested that the rowset be created from a
   // Command object, create a Command, set its properties and
   // text and execute it to create the Rowset object
   if( g_dwFlags & USE_COMMAND )
      WCHAR      wszCommandText[MAX_NAME_LEN + 1];

      // Attempt to create the Command object from the provider's
      // Session object. Note that Commands are not supported by
      // all providers, and this will fail in that case
      CHECK_HR(hr = myCreateCommand(pUnkSession, &pUnkCommand));
      // Get the command text that we will execute from the user
      if( !myGetInputFromUser(wszCommandText, L"\nType the command "
         L"to execute [Enter = `select * from %s`]: ", wszTableName) )
         if (_snwprintf_s(wszCommandText, sizeof(wszCommandText ), MAX_NAME_LEN, 
                L"select * from %s", wszTableName) < 0)
                return S_FALSE;
                wszCommandText[MAX_NAME_LEN] = L'\0';

      // And execute the Command the user entered
      CHECK_HR(hr = myExecuteCommand(pUnkCommand, wszCommandText,
               1, rgPropSets, ppUnkRowset));
   // Otherwise, the user gets the default behavior, which is to use
   // IOpenRowset to create the Rowset object from the Session object.
   // IOpenRowset is supported by all providers; it takes a TableID
   // and creates a rowset containing all rows in that table. It is
   // similar to using SQL command text of "select * from TableID"
      DBID            TableID;

      // Create the TableID
      TableID.eKind            = DBKIND_NAME;
      TableID.uName.pwszName   = wszTableName;

      // Obtain the table name from the user
      myGetInputFromUser(wszTableName, L"\nType the name of the table "
         L"to use [Enter = `%s`]: ", wszTableName);

      // Get the IOpenRowset interface and create a Rowset object
      // over the requested table through OpenRowset
      XCHECK_HR(hr = pUnkSession->QueryInterface(
               IID_IOpenRowset, (void**)&pIOpenRowset));
      XCHECK_HR(hr = pIOpenRowset->OpenRowset(
               NULL,         //pUnkOuter
               &TableID,      //pTableID
               NULL,         //pIndexID
               IID_IRowset,   //riid
               1,            //cPropSets
               rgPropSets,      //rgPropSets
               ppUnkRowset      //ppRowset

   if( pIOpenRowset )
   if( pUnkCommand )
   return hr;