DeleteRule, propriété – Exemple (VC++)

S’applique à : Access 2013, Office 2013

Cet exemple illustre la propriété DeleteRule d'un objet Key. Le code ajoute un nouvel objet Table, puis définit une nouvelle clé primaire en attribuant la valeur adRICascade à la propriété DeleteRule.

 
// BeginDeleteRuleCpp 
#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 DeleteRuleX(void); 
 
////////////////////////////////////////////////////////// 
// // 
// Main Function // 
// // 
////////////////////////////////////////////////////////// 
void main() 
{ 
 if(FAILED(::CoInitialize(NULL))) 
 return; 
 
 DeleteRuleX(); 
 
 ::CoUninitialize(); 
} 
 
////////////////////////////////////////////////////////// 
// // 
// DeleteRuleX Function // 
// // 
////////////////////////////////////////////////////////// 
void DeleteRuleX(void) 
{ 
 HRESULT hr = S_OK; 
 
 // Define ADOX object pointers. 
 // Initialize pointers on define. 
 // These are in the ADOX:: namespace. 
 _KeyPtr m_pKeyPrimary = NULL; 
 _CatalogPtr m_pCatalog = NULL; 
 _TablePtr m_pTblNew = NULL; 
 
 // Define 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_pKeyPrimary.CreateInstance(__uuidof(Key))); 
 TESTHR(hr = m_pCatalog.CreateInstance(__uuidof (Catalog))); 
 TESTHR(hr = m_pTblNew.CreateInstance(__uuidof(Table))); 
 
 // Connect the catalog. 
 m_pCatalog->PutActiveConnection(strcnn); 
 
 // Name new table. 
 m_pTblNew->Name = "NewTable"; 
 
 // Append a numeric and a text field to new table. 
 m_pTblNew->Columns->Append("NumField",adInteger,20); 
 m_pTblNew->Columns->Append("TextField",adVarWChar,20); 
 
 // Append the new table. 
 m_pCatalog->Tables->Append(_variant_t((IDispatch*)m_pTblNew)); 
 printf("Table 'NewTable' is added.\n"); 
 
 // Define the Primary key. 
 m_pKeyPrimary->Name = "NumField"; 
 m_pKeyPrimary->Type = adKeyPrimary; 
 m_pKeyPrimary->RelatedTable = "Customers"; 
 m_pKeyPrimary->Columns->Append("NumField",adInteger,20); 
 m_pKeyPrimary->Columns->GetItem("NumField")->RelatedColumn = 
 "CustomerId"; 
 m_pKeyPrimary->DeleteRule = adRICascade; 
 
 //to pass an optional column parameter to Key's Apppend method 
 _variant_t vOptional; 
 vOptional.vt = VT_ERROR; 
 vOptional.scode = DISP_E_PARAMNOTFOUND; 
 
 // Append the primary key. 
 m_pCatalog->Tables->GetItem("NewTable")->Keys->Append( 
 _variant_t((IDispatch*)m_pKeyPrimary), 
 adKeyPrimary,vOptional,L"",L""); 
 
 // Delete the table as this is a demonstration. 
 m_pCatalog->Tables->Delete(m_pTblNew->Name); 
 printf("Table 'NewTable' is deleted.\n"); 
 } 
 
 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 include files...."<< endl; 
 } 
} 
// EndDeleteRuleCpp