Clustered-Eigenschaft – Beispiel (VC++)
In diesem Beispiel wird die Clustered-Eigenschaft eines Index veranschaulicht. Beachten Sie, dass Microsoft Jet-Datenbanken keine gruppierten Indizes unterstützen, weshalb in diesem Beispiel False für die Clustered-Eigenschaft aller Indizes in der Northwind-Datenbank zurückgegeben wird.
// BeginClusteredCpp.cpp
// compile with: /EHsc
#import "msadox.dll" no_namespace
#include "iostream"
using namespace std;
// Function declarations
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void ClusteredX();
int main() {
if ( FAILED(::CoInitialize(NULL) ) )
return -1;
ClusteredX();
::CoUninitialize();
}
void ClusteredX() {
HRESULT hr = S_OK;
// Define ADOX object pointers, initialize pointers. These are in ADODB namespace.
_CatalogPtr m_pCatalog = NULL;
_TablePtr m_pTable = NULL;
_IndexPtr m_pIndex = NULL;
// Define other variables here
_variant_t vIndex;
try {
TESTHR(hr = m_pCatalog.CreateInstance(__uuidof(Catalog)));
// Connect to the catalog.
m_pCatalog->PutActiveConnection("Provider='Microsoft.JET.OLEDB.4.0';data source='c:\\Northwind.mdb';");
// Enumerate Tables.
for (short iTable = 0 ; iTable < m_pCatalog->Tables->Count ; iTable++ ) {
vIndex = iTable;
m_pTable = m_pCatalog->Tables->GetItem(vIndex);
// Enumerate Indexes.
for (short iIndex = 0 ; iIndex < m_pTable->Indexes->Count ; iIndex++) {
vIndex = iIndex;
m_pIndex = m_pTable->Indexes->GetItem(vIndex);
cout << m_pTable->Name << " " ;
cout << m_pIndex->Name << " " << (m_pIndex->GetClustered() ? "True" : "False") << 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 occurred in ClusteredX...."<< endl;
}
}