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Append and CreateParameter Methods Example (VC++)

This example uses the Append and CreateParameter methods to execute a stored procedure with an input parameter.

// BeginAppendCpp.cpp
// compile with: /EHsc
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")

#include <ole2.h>
#include <stdio.h>
#include "conio.h"
#include "icrsint.h"

// class extracts only author id,fname,lastname
class CEmployeeRs : public CADORecordBinding {
   BEGIN_ADO_BINDING(CEmployeeRs)
    
   // Column au_id is the 1st field in the recordset   
   ADO_VARIABLE_LENGTH_ENTRY2(1, adVarChar, m_szau_id, sizeof(m_szau_id), lau_idStatus, TRUE)

    ADO_VARIABLE_LENGTH_ENTRY2(2, adVarChar, m_szau_lname, sizeof(m_szau_lname), lau_lnameStatus, TRUE)

    ADO_VARIABLE_LENGTH_ENTRY2(3, adVarChar, m_szau_fname, sizeof(m_szau_fname), lau_fnameStatus, TRUE)
   
END_ADO_BINDING()

public:
   CHAR m_szau_id[20];
   ULONG lau_idStatus;
   CHAR m_szau_fname[40];
   ULONG lau_fnameStatus;
   CHAR   m_szau_lname[40];
   ULONG  lau_lnameStatus;
};

// Function declaration
inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };
void AppendX();
void PrintProviderError(_ConnectionPtr pConnection);

int main() {
   HRESULT hr = S_OK;

   if (FAILED(::CoInitialize(NULL)))
        return -1;

    AppendX();
    ::CoUninitialize(); 
}

void AppendX() {
   HRESULT hr = S_OK;

   // Define ADO object pointers. Initialize pointers on define. These are in the ADODB::  namespace.
   _RecordsetPtr pRstByRoyalty = NULL;
   _RecordsetPtr pRstAuthors = NULL;  
   _CommandPtr pcmdByRoyalty = NULL;
   _ParameterPtr pprmByRoyalty = NULL;
   _ConnectionPtr pConnection = NULL;

   //Define Other variables
   IADORecordBinding *picRs = NULL;   // Interface Pointer declared.(VC++ Extensions)   
   CEmployeeRs emprs;   // C++ class object    

   _bstr_t strCnn("Provider='sqloledb'; Data Source='My_Data_Source'; Initial Catalog='pubs'; Integrated Security='SSPI';");

   _bstr_t strMessage, strAuthorID;

   int intRoyalty;
   VARIANT vtRoyalty;

   try {
      // Open a Connection.
      TESTHR(pConnection.CreateInstance(__uuidof(Connection)));
      hr = pConnection->Open(strCnn, "", "", adConnectUnspecified);
      pConnection->CursorLocation = adUseClient;

      // Open Command Object with one Parameter
      TESTHR(pcmdByRoyalty.CreateInstance(__uuidof(Command)));
      pcmdByRoyalty->CommandText = "byroyalty";
      pcmdByRoyalty->CommandType = adCmdStoredProc;

      // Get parameter value and append parameter
      printf("Enter Royalty: ");
      scanf_s("%d", &intRoyalty);

      // Define Integer/variant.
      vtRoyalty.vt = VT_I2;
      vtRoyalty.iVal = intRoyalty;
      pprmByRoyalty = pcmdByRoyalty->CreateParameter("percentage", adInteger, adParamInput, sizeof(int), vtRoyalty);
      pcmdByRoyalty->Parameters->Append(pprmByRoyalty);

      pprmByRoyalty->Value = vtRoyalty;

      // Create Recordset by executing the command
      pcmdByRoyalty->ActiveConnection = pConnection;
      pRstByRoyalty = pcmdByRoyalty->Execute(NULL, NULL, adCmdStoredProc);

      // Open the authors table to get author names for display
      TESTHR(pRstAuthors.CreateInstance(__uuidof(Recordset)));

      // You have to explicitly pass the default Cursor type and LockType to the Recordset here
      hr = pRstAuthors->Open("authors", _variant_t((IDispatch*)pConnection, true), adOpenForwardOnly, adLockReadOnly, adCmdTable); 

      // Open an IADORecordBinding interface pointer which we'll use for Binding Recordset to a class    
      TESTHR(pRstAuthors->QueryInterface(__uuidof(IADORecordBinding), (LPVOID*)&picRs));

      // Bind the Recordset to a C++ Class here    
      TESTHR(picRs->BindToRecordset(&emprs));

      //Print current data in the recordset, adding author names from author table.
      printf("Authors with %d percent royalty ", intRoyalty);

      while(!(pRstByRoyalty->EndOfFile)) {
         strAuthorID = pRstByRoyalty->Fields->Item["au_id"]->Value;
         pRstAuthors->Filter = "au_id = '"+strAuthorID+"'";

         printf("\n"  "%s, %s  %s",emprs.lau_idStatus == adFldOK ? emprs.m_szau_id : "<NULL>",\
            emprs.lau_fnameStatus == adFldOK ? emprs.m_szau_fname : "<NULL>",\
            emprs.lau_lnameStatus == adFldOK ? emprs.m_szau_lname : "<NULL>");

         pRstByRoyalty->MoveNext(); 
      }
   }
   catch(_com_error &e) {
      _bstr_t bstrSource(e.Source());
      _bstr_t bstrDescription(e.Description());
      PrintProviderError(pConnection);
      printf("\n Source : %s \n Description : %s \n", (LPCSTR)bstrSource, (LPCSTR)bstrDescription);
   }

   // Clean up objects before exit.  Release the IADORecordset Interface here   
   if (picRs)
      picRs->Release();

   if (pRstByRoyalty)
      if (pRstByRoyalty->State == adStateOpen)
         pRstByRoyalty->Close();
   if (pRstAuthors)
      if (pRstAuthors->State == adStateOpen)
         pRstAuthors->Close();
   if (pConnection)
      if (pConnection->State == adStateOpen)
         pConnection->Close();
}

void PrintProviderError(_ConnectionPtr pConnection) {
    // Print Provider Errors from Connection object.
    // pErr is a record object in the Connection's Error collection.
    ErrorPtr pErr = NULL;
    long nCount = 0;
    long i = 0;

    if ( (pConnection->Errors->Count) > 0) {
        nCount = pConnection->Errors->Count;
        // Collection ranges from 0 to nCount -1.
        for (i = 0 ; i < nCount ; i++) {
            pErr = pConnection->Errors->GetItem(i);
            printf("Error number: %x\n Error Description: %s\n", pErr->Number, (LPCSTR) pErr->Description);
        }
    }
}

Input

25

Authors with 25 percent royalty
724-80-9391, Stearns  MacFeather
899-46-2035, Anne  Ringer
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