Exemple de propriétés ADO NumericScale et Precision (VC++)

S’applique à : Access 2013, Office 2013

Cet exemple utilise les propriétés NumericScale et Precision pour afficher l’échelle numérique et la précision des champs dans la table Remises de la base de données Pubs .

 
// BeginNumericScaleCpp 
#import "C:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile") 
 
#include <ole2.h> 
#include <stdio.h> 
#include <conio.h> 
 
// Function declarations 
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);}; 
void NumericScaleX(void); 
void PrintProviderError(_ConnectionPtr pConnection); 
void PrintComError(_com_error &e); 
 
/////////////////////////////////////////////////////////// 
// // 
// Main Function // 
// // 
/////////////////////////////////////////////////////////// 
 
void main() 
{ 
 if(FAILED(::CoInitialize(NULL))) 
 return; 
 
 NumericScaleX(); 
 
 ::CoUninitialize(); 
} 
 
/////////////////////////////////////////////////////////// 
// // 
// NumericScaleX Function // 
// // 
/////////////////////////////////////////////////////////// 
 
void NumericScaleX(void) 
{ 
 // Define ADO object pointers. 
 // Initialize pointers on define. 
 // These are in the ADODB:: namespace 
 _RecordsetPtr pRstDiscounts = NULL; 
 FieldsPtr fldTemp = NULL; 
 
 //Define Other Variables 
 HRESULT hr = S_OK; 
 _variant_t Index; 
 Index.vt = VT_I2; 
 
 _bstr_t strCnn("Provider='sqloledb';Data Source='MySqlServer';" 
 "Initial Catalog='pubs';Integrated Security='SSPI';"); 
 
 try 
 { 
 // Open recordset. 
 TESTHR(pRstDiscounts.CreateInstance(__uuidof(Recordset))); 
 pRstDiscounts->Open("discounts", strCnn, adOpenForwardOnly, 
 adLockReadOnly, adCmdTable); 
 
 // Display numeric scale and precision of 
 // numeric and small integer fields. 
 fldTemp = pRstDiscounts->GetFields(); 
 
 for (int intLoop=0;intLoop < (int)fldTemp->GetCount();intLoop++) 
 { 
 Index.iVal = intLoop; 
 
 if ((fldTemp->GetItem(Index)->Type == adNumeric) 
 || (fldTemp->GetItem(Index)->Type == adSmallInt)) 
 { 
 printf("Field: %s\n" ,(LPCSTR)fldTemp-> 
 GetItem(Index)->GetName()); 
 printf("Numeric scale: %d\n", fldTemp-> 
 GetItem(Index)->GetNumericScale()); 
 printf("Precision: %d\n", fldTemp-> 
 GetItem(Index)->GetPrecision()); 
 } 
 } 
 } 
 catch(_com_error &e) 
 { 
 // Notify the user of errors if any. 
 // Pass a connection pointer accessed from the Recordset. 
 _variant_t vtConnect = pRstDiscounts->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; 
 } 
 } 
 
 // Clean up objects before exit. 
 if (pRstDiscounts) 
 if (pRstDiscounts->State == adStateOpen) 
 pRstDiscounts->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("\t Error number: %x\t%s", pErr->Number, 
 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); 
} 
// EndNumericScaleCpp