Ejemplo de la propiedad Status (VC++)

Se aplica a: Access 2013, Office 2013

En este ejemplo se utiliza la propiedad Status para mostrar qué registros se han modificado en una operación por lotes antes de que se haya producido una actualización por lotes.

 
// BeginStatusCpp 
#import "c:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile") 
 
#include <ole2.h> 
#include <stdio.h> 
#include <conio.h> 
#include "StatusX.h" 
 
// Function declarations 
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);}; 
void StatusX(void); 
void PrintProviderError(_ConnectionPtr pConnection); 
void PrintComError(_com_error &e); 
 
/////////////////////////////////////////////// 
// // 
// Main Function // 
// // 
/////////////////////////////////////////////// 
 
void main() 
{ 
 if(FAILED(CoInitialize(NULL))) 
 return; 
 
 StatusX(); 
 
 ::CoUninitialize(); 
} 
 
/////////////////////////////////////////////// 
// // 
// StatusX Function // 
// // 
/////////////////////////////////////////////// 
void StatusX(void) 
{ 
 HRESULT hr = S_OK; 
 
 // Define string variables. 
 _bstr_t strCnn("Provider='sqloledb';Data Source='MySqlServer';" 
 "Initial Catalog='pubs';Integrated Security='SSPI';"); 
 
 // Define ADO object pointers. 
 // Initialize pointers on define. 
 // These are in the ADODB:: namespace. 
 IADORecordBinding *picRs = NULL; // Interface Pointer Declared 
 CTitleRs titlers; // C++ Class Object 
 _RecordsetPtr pRstTitles = NULL; 
 LPSTR p_TempStr = NULL; 
 
 try 
 { 
 // Open recordset for batch update 
 TESTHR(hr = pRstTitles.CreateInstance(__uuidof(Recordset))); 
 pRstTitles->CursorType = adOpenKeyset; 
 pRstTitles->LockType = adLockBatchOptimistic; 
 pRstTitles->Open ("titles", strCnn, 
 adOpenKeyset, adLockBatchOptimistic, adCmdTable); 
 
 // Open an IADORecordBinding interface pointer which 
 // we will use for binding Recordset to a class. 
 TESTHR(hr = pRstTitles->QueryInterface( 
 __uuidof(IADORecordBinding),(LPVOID*)&picRs)); 
 
 // Bind the Recordset to a C++ class here 
 TESTHR(hr = picRs->BindToRecordset(&titlers)); 
 
 p_TempStr = (LPSTR) malloc(sizeof(titlers.m_szt_Type)); 
 
 // Change the type of psychology titles. 
 while(!(pRstTitles->EndOfFile)) 
 { 
 // Set the final character of the destination string to NULL. 
 p_TempStr[sizeof(titlers.m_szt_Type)-1] = '\0'; 
 // The source string will get truncated if its length is 
 // longer than the length of the destination string minus one. 
 strncpy(p_TempStr,strtok(titlers.m_szt_Type," "), 
 sizeof(titlers.m_szt_Type)-1); 
 
 // Compare the type of psychology titles 
 if (!strcmp(p_TempStr,"psychology")) 
 { 
 // Copy "self_help" title field 
 pRstTitles->Fields->GetItem("type")->Value = 
 (_bstr_t) ("self_help"); 
 } 
 pRstTitles->MoveNext(); 
 } 
 
 // Display Title ID and status 
 pRstTitles->MoveFirst(); 
 while(!(pRstTitles->EndOfFile)) 
 { 
 if(pRstTitles->Status == adRecModified) 
 { 
 printf("%s - Modified\n",titlers.lt_Title_idStatus == 
 adFldOK ? titlers.m_szt_Title_id : "<NULL>"); 
 } 
 else 
 { 
 printf("%s\n",titlers.lt_Title_idStatus == adFldOK ? 
 titlers.m_szt_Title_id : "<NULL>"); 
 } 
 pRstTitles->MoveNext(); 
 } 
 } 
 catch (_com_error &e) 
 { 
 // Notify the user of errors if any. 
 // Pass a connection pointer accessed from the Recordset. 
 _variant_t vtConnect = pRstTitles->GetActiveConnection(); 
 
 // GetActiveConnection returns connect string if connection 
 // is not open, else returns Connection object. 
 switch(vtConnect.vt) 
 { 
 case VT_BSTR: 
 PrintComError(e); 
 break; 
 case VT_DISPATCH: 
 PrintProviderError(vtConnect); 
 break; 
 default: 
 printf("Errors occured."); 
 break; 
 } 
 } 
 
 // Deallocate the memory 
 if (p_TempStr) 
 free(p_TempStr); 
 
 if (pRstTitles) 
 if (pRstTitles->State == adStateOpen) 
 { 
 // Cancel the update because this is a demonstration. 
 pRstTitles->CancelBatch(adAffectAll); 
 pRstTitles->Close(); 
 } 
} 
 
/////////////////////////////////////////////// 
// // 
// PrintProviderError Function // 
// // 
/////////////////////////////////////////////// 
 
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("Error number: %x\t%s\n", pErr->Number, 
 (LPCSTR) pErr->Description); 
 } 
 } 
} 
 
/////////////////////////////////////////////// 
// // 
// PrintComError Function // 
// // 
/////////////////////////////////////////////// 
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); 
} 
// EndStatusCpp 

StatusX.h

 
// BeginStatusH 
#include "icrsint.h" 
 
//This class extracts title_id and type from titles table. 
class CTitleRs : public CADORecordBinding 
{ 
 BEGIN_ADO_BINDING(CTitleRs) 
 // Column title_id is the 1st field in the table 
 ADO_VARIABLE_LENGTH_ENTRY2(1,adVarChar,m_szt_Title_id, 
 sizeof(m_szt_Title_id),lt_Title_idStatus,FALSE) 
 // Column type is the 3rd field in the table 
 ADO_VARIABLE_LENGTH_ENTRY2(3,adVarChar,m_szt_Type, 
 sizeof(m_szt_Type),lt_TypeStatus,TRUE) 
END_ADO_BINDING() 
 
public: 
 CHAR m_szt_Title_id[7]; 
 ULONG lt_Title_idStatus; 
 CHAR m_szt_Type[13]; 
 ULONG lt_TypeStatus; 
}; 
// EndStatusH