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Find Method Example (VC++)

This example uses the Recordset object's Find method to locate and count the number of business titles in the Pubs database. The example assumes the underlying provider does not support similar functionality.

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

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

// This Class extracts only titleId from Titles table.
class CTitlesRs : public CADORecordBinding {
BEGIN_ADO_BINDING(CTitlesRs)

   // Column title_id is the first field in the recordset from Titles table.
   ADO_VARIABLE_LENGTH_ENTRY2(1, adVarChar, m_szt_titleid, sizeof(m_szt_titleid), lt_titleidStatus, FALSE)

END_ADO_BINDING()

public:
   CHAR m_szt_titleid[150];
   ULONG lt_titleidStatus;
};

// Function declarations
inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };
void FindX();
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);

int main() {
   if ( FAILED(::CoInitialize(NULL)) )
      return -1;
   FindX();
   ::CoUninitialize();
}

void FindX() {
   // Define ADO object pointers.  Initialize pointers on define.
   // These are in the ADODB::  namespace.
   _ConnectionPtr pConnection = NULL;
   _RecordsetPtr pRstTitles = NULL;
   IADORecordBinding *picRs = NULL;   // Interface Pointer declared.
   CTitlesRs titlers;   // C++ class object

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

   try {
      // Open connection.
      TESTHR(pConnection.CreateInstance(__uuidof(Connection)));
      pConnection->Open (strCnn, "", "", adConnectUnspecified);

      // Open title Table
      TESTHR(pRstTitles.CreateInstance(__uuidof(Recordset)));

      pRstTitles->Open("SELECT title_id FROM titles", 
         _variant_t((IDispatch *)pConnection), 
         adOpenStatic, adLockReadOnly, adCmdText);

      // The default parameters are sufficient to search forward through a Recordset.

      pRstTitles->Find ("title_id LIKE 'BU%'", 0, adSearchForward, "");

      // Open an IADORecordBinding interface pointer for Binding Recordset to a class    
      TESTHR(pRstTitles->QueryInterface(__uuidof(IADORecordBinding), (LPVOID*)&picRs));

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

      // Skip the current record to avoid finding the same row repeatedly. 
      // The bookmark is redundant because Find searches from the current position.
      int count = 0;

      // Continue if last find succeeded.
      while (!(pRstTitles->EndOfFile)) {
         printf("Title ID: %s\n", titlers.lt_titleidStatus == adFldOK ?
            titlers.m_szt_titleid : "<NULL>");
         count++;   // Count the last title found.

         _variant_t mark = pRstTitles->Bookmark;   // Note current pos.
         pRstTitles->Find("title_id LIKE 'BU%'", 1, adSearchForward, mark);
      }
      printf("The number of business titles is %d\n", count);
   }
   catch(_com_error &e) {
      // Display errors, if any. Pass connection pointer accessed from the Recordset.
      PrintProviderError(pConnection);
      PrintComError(e);
   }    

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

   if (pRstTitles)
      if (pRstTitles->State == adStateOpen)
         pRstTitles->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;

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

void PrintComError(_com_error &e) {
   _bstr_t bstrSource(e.Source());
   _bstr_t bstrDescription(e.Description());

   // Print Com errors.
   printf("Error\n");
   printf("\tCode = %08lx\n", e.Error());
   printf("\tCode meaning = %s\n", e.ErrorMessage());
   printf("\tSource = %s\n", (LPCSTR) bstrSource);
   printf("\tDescription = %s\n", (LPCSTR) bstrDescription);
}
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