Примеры методов Append и CreateParameter (VC++)
В этом примере используются методы Append и CreateParameter для выполнения хранимой процедуры с входным параметром.
Пример
// BeginAppendCpp.cpp
// compile with: /EHsc
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")
#include <ole2.h>
#include <stdio.h>
#include "conio.h"
#include "icrsint.h"
// class extracts only author id,fname,lastname
class CEmployeeRs : public CADORecordBinding {
BEGIN_ADO_BINDING(CEmployeeRs)
// Column au_id is the 1st field in the recordset
ADO_VARIABLE_LENGTH_ENTRY2(1, adVarChar, m_szau_id, sizeof(m_szau_id), lau_idStatus, TRUE)
ADO_VARIABLE_LENGTH_ENTRY2(2, adVarChar, m_szau_lname, sizeof(m_szau_lname), lau_lnameStatus, TRUE)
ADO_VARIABLE_LENGTH_ENTRY2(3, adVarChar, m_szau_fname, sizeof(m_szau_fname), lau_fnameStatus, TRUE)
END_ADO_BINDING()
public:
CHAR m_szau_id[20];
ULONG lau_idStatus;
CHAR m_szau_fname[40];
ULONG lau_fnameStatus;
CHAR m_szau_lname[40];
ULONG lau_lnameStatus;
};
// Function declaration
inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };
void AppendX();
void PrintProviderError(_ConnectionPtr pConnection);
int main() {
HRESULT hr = S_OK;
if (FAILED(::CoInitialize(NULL)))
return -1;
AppendX();
::CoUninitialize();
}
void AppendX() {
HRESULT hr = S_OK;
// Define ADO object pointers. Initialize pointers on define. These are in the ADODB:: namespace.
_RecordsetPtr pRstByRoyalty = NULL;
_RecordsetPtr pRstAuthors = NULL;
_CommandPtr pcmdByRoyalty = NULL;
_ParameterPtr pprmByRoyalty = NULL;
_ConnectionPtr pConnection = NULL;
//Define Other variables
IADORecordBinding *picRs = NULL; // Interface Pointer declared.(VC++ Extensions)
CEmployeeRs emprs; // C++ class object
_bstr_t strCnn("Provider='sqloledb'; Data Source='My_Data_Source'; Initial Catalog='pubs'; Integrated Security='SSPI';");
_bstr_t strMessage, strAuthorID;
int intRoyalty;
VARIANT vtRoyalty;
try {
// Open a Connection.
TESTHR(pConnection.CreateInstance(__uuidof(Connection)));
hr = pConnection->Open(strCnn, "", "", adConnectUnspecified);
pConnection->CursorLocation = adUseClient;
// Open Command Object with one Parameter
TESTHR(pcmdByRoyalty.CreateInstance(__uuidof(Command)));
pcmdByRoyalty->CommandText = "byroyalty";
pcmdByRoyalty->CommandType = adCmdStoredProc;
// Get parameter value and append parameter
printf("Enter Royalty: ");
scanf_s("%d", &intRoyalty);
// Define Integer/variant.
vtRoyalty.vt = VT_I2;
vtRoyalty.iVal = intRoyalty;
pprmByRoyalty = pcmdByRoyalty->CreateParameter("percentage", adInteger, adParamInput, sizeof(int), vtRoyalty);
pcmdByRoyalty->Parameters->Append(pprmByRoyalty);
pprmByRoyalty->Value = vtRoyalty;
// Create Recordset by executing the command
pcmdByRoyalty->ActiveConnection = pConnection;
pRstByRoyalty = pcmdByRoyalty->Execute(NULL, NULL, adCmdStoredProc);
// Open the authors table to get author names for display
TESTHR(pRstAuthors.CreateInstance(__uuidof(Recordset)));
// You have to explicitly pass the default Cursor type and LockType to the Recordset here
hr = pRstAuthors->Open("authors", _variant_t((IDispatch*)pConnection, true), adOpenForwardOnly, adLockReadOnly, adCmdTable);
// Open an IADORecordBinding interface pointer which we'll use for Binding Recordset to a class
TESTHR(pRstAuthors->QueryInterface(__uuidof(IADORecordBinding), (LPVOID*)&picRs));
// Bind the Recordset to a C++ Class here
TESTHR(picRs->BindToRecordset(&emprs));
//Print current data in the recordset, adding author names from author table.
printf("Authors with %d percent royalty ", intRoyalty);
while(!(pRstByRoyalty->EndOfFile)) {
strAuthorID = pRstByRoyalty->Fields->Item["au_id"]->Value;
pRstAuthors->Filter = "au_id = '"+strAuthorID+"'";
printf("\n" "%s, %s %s",emprs.lau_idStatus == adFldOK ? emprs.m_szau_id : "<NULL>",\
emprs.lau_fnameStatus == adFldOK ? emprs.m_szau_fname : "<NULL>",\
emprs.lau_lnameStatus == adFldOK ? emprs.m_szau_lname : "<NULL>");
pRstByRoyalty->MoveNext();
}
}
catch(_com_error &e) {
_bstr_t bstrSource(e.Source());
_bstr_t bstrDescription(e.Description());
PrintProviderError(pConnection);
printf("\n Source : %s \n Description : %s \n", (LPCSTR)bstrSource, (LPCSTR)bstrDescription);
}
// Clean up objects before exit. Release the IADORecordset Interface here
if (picRs)
picRs->Release();
if (pRstByRoyalty)
if (pRstByRoyalty->State == adStateOpen)
pRstByRoyalty->Close();
if (pRstAuthors)
if (pRstAuthors->State == adStateOpen)
pRstAuthors->Close();
if (pConnection)
if (pConnection->State == adStateOpen)
pConnection->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;
long nCount = 0;
long i = 0;
if ( (pConnection->Errors->Count) > 0) {
nCount = pConnection->Errors->Count;
// Collection ranges from 0 to nCount -1.
for (i = 0 ; i < nCount ; i++) {
pErr = pConnection->Errors->GetItem(i);
printf("Error number: %x\n Error Description: %s\n", pErr->Number, (LPCSTR) pErr->Description);
}
}
}
Входные данные
25
Пример выходных данных
Authors with 25 percent royalty
724-80-9391, Stearns MacFeather
899-46-2035, Anne Ringer