NumericScale et Precision, propriétés – Exemple (VC++)

S’applique à : Access 2013, Office 2013

Cet exemple illustre les propriétés NumericScale et Precision de l’objet Column. Ce code affiche leur valeur pour la table Order Details de la base de données Northwind.

 
// BeginNumericScalePrecCpp 
#import "c:\Program Files\Common Files\system\ado\msadox.dll" no_namespace 
#import "c:\Program Files\Common Files\system\ado\msado15.dll" 
 
#include "iostream.h" 
#include "stdio.h" 
#include "conio.h" 
 
//Function declarations 
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);}; 
void NumericScalePrecX(void); 
 
////////////////////////////////////////////////////////// 
// // 
// Main Function // 
// // 
////////////////////////////////////////////////////////// 
void main() 
{ 
 if(FAILED(::CoInitialize(NULL))) 
 return; 
 
 NumericScalePrecX(); 
 
 ::CoUninitialize(); 
} 
 
////////////////////////////////////////////////////////// 
// // 
// NumericScalePrecX Function // 
// // 
////////////////////////////////////////////////////////// 
void NumericScalePrecX(void) 
{ 
 HRESULT hr = S_OK; 
 
 // Define ADOX object pointers. 
 // Initialize pointers on define. 
 // These are in the ADOX:: namespace. 
 _CatalogPtr m_pCatalog = NULL; 
 _TablePtr m_pTable = NULL; 
 _ColumnPtr m_pColumn = NULL; 
 
 //Define ADODB object pointers 
 ADODB::_ConnectionPtr m_pCnn = NULL; 
 
 //Declare string variables 
 _bstr_t strCnn("Provider='Microsoft.JET.OLEDB.4.0';" 
 "Data Source='c:\\Program Files\\Microsoft Office\\" 
 "Office\\Samples\\Northwind.mdb';"); 
 try 
 { 
 TESTHR(hr = m_pCnn.CreateInstance(__uuidof(ADODB::Connection))); 
 
 TESTHR(hr = m_pCatalog.CreateInstance(__uuidof (Catalog))); 
 
 // Connect the catalog. 
 m_pCnn->Open (strCnn, "", "", NULL); 
 
 m_pCatalog->PutActiveConnection(variant_t((IDispatch *)m_pCnn)); 
 
 // Retrieve the Order Details table 
 m_pTable = m_pCatalog->Tables->GetItem("Order Details"); 
 
 // Display numeric scale and precision of 
 // small integer fields. 
 _variant_t vIndex; 
 for (long lIndex=0; lIndex < m_pTable->Columns->Count; lIndex++) 
 { 
 vIndex = lIndex ; 
 m_pColumn = m_pTable->Columns->GetItem(vIndex); 
 if(m_pColumn->Type == adSmallInt) 
 { 
 cout << "Column: " << m_pColumn->GetName() << endl; 
 cout << "Numeric scale: " << (_bstr_t) m_pColumn-> 
 GetNumericScale() << endl; 
 cout << "Precision: " << m_pColumn->GetPrecision() << 
 endl; 
 } 
 } 
 } 
 catch(_com_error &e) 
 { 
 // Notify the user of errors if any. 
 _bstr_t bstrSource(e.Source()); 
 _bstr_t bstrDescription(e.Description()); 
 
 printf("\n\tSource : %s \n\tdescription : %s \n ", 
 (LPCSTR)bstrSource,(LPCSTR)bstrDescription); 
 } 
 catch(...) 
 { 
 cout << "Error occured in NumericScalePrecX...."<< endl; 
 } 
} 
// EndNumericScalePrecCpp