NextRecordset, exemple de méthode (VC++)
Cet exemple utilise la méthode NextRecordset pour afficher les données d’un Recordset qui utilise une instruction de commande composée constituée de trois instructions SELECT distinctes.
// BeginNextRecordsetCpp.cpp
// compile with: /EHsc
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")
#include <stdio.h>
#include <ole2.h>
#include <conio.h>
#include <stdlib.h>
//Function Declaration.
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void NextRecordsetX();
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);
int main() {
if (FAILED(::CoInitialize(NULL)))
return -1;
NextRecordsetX();
::CoUninitialize();
}
void NextRecordsetX() {
// Define ADO object pointers. Initialize pointers on define. These are in the ADODB:: namespace.
_RecordsetPtr pRstCompound = NULL;
// Define Other Variables
_variant_t index;
index.vt = VT_I2;
// Assign connection string to a variable.
_bstr_t strCnn("Provider='sqloledb';Data Source='(local)';Initial Catalog='pubs';Integrated Security='SSPI';");
try {
// Open recordset from Authors table.
TESTHR(pRstCompound.CreateInstance(__uuidof(Recordset)));
// Pass the Cursor type and Lock type to the Recordset.
pRstCompound->Open("SELECT * FROM authors; SELECT * FROM stores;SELECT * FROM jobs",
strCnn, adOpenForwardOnly, adLockReadOnly, adCmdText);
// Display results from each SELECT statement.
int intCount = 1;
while (!(pRstCompound == NULL)) {
printf("\n\nContents of recordset #%d\n", intCount);
while (!pRstCompound->EndOfFile) {
index.iVal = 0;
printf("%s\t", (LPCSTR)(_bstr_t)pRstCompound->GetFields()->GetItem(& index)->Value);
index.iVal = 1;
printf("%s\n", (LPCSTR)(_bstr_t)pRstCompound->Fields->GetItem(& index)->Value);
pRstCompound->MoveNext();
}
long lngRec = 0;
pRstCompound = pRstCompound->NextRecordset((VARIANT *)lngRec);
intCount = intCount + 1;
}
}
catch(_com_error &e) {
// Notify the user of errors if any. Pass a connection pointer accessed from the Recordset.
_variant_t vtConnect = pRstCompound->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 occurred.");
break;
}
}
// Clean up objects before exit.
if (pRstCompound)
if (pRstCompound->State == adStateOpen)
pRstCompound->Close();
}
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, (LPCSTR) pErr->Description);
}
}
}
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);
}
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