Eseguire una funzione definita dall'utente ed elaborare il codice restituito (OLE DB)
Si applica a:
SQL Server Azure SQL DatabaseIstanza gestita di SQL di AzureAzure Synapse Analytics AnalyticsPlatform System (PDW)
In questo esempio viene eseguita una funzione definita dall'utente e viene stampato il codice restituito. Questo esempio non è supportato in IA64.
Questo esempio usa il database oledbtest come esempio. Sostituirlo con qualsiasi database SQL Server disponibile.
Importante
Se possibile, usare l'autenticazione di Windows. Se non è disponibile, agli utenti verrà richiesto di immettere le credenziali in fase di esecuzione. Evitare di archiviare le credenziali in un file. Se è necessario rendere persistenti le credenziali, è consigliabile crittografarle usando l'API di crittografia Win32.
Esempio
Eseguire il primo elenco codici (Transact-SQL) per creare la stored procedure usata dall'applicazione.
Compilare il secondo listato di codice (C++) con ole32.lib oleaut32.lib ed eseguirlo. In questa applicazione viene eseguita la connessione all'istanza predefinita di SQL Server nel computer in uso. In alcuni sistemi operativi Windows sarà necessario modificare (local) o (localhost) impostando il valore sul nome dell'istanza di SQL Server. Per connettersi a un'istanza denominata, modificare la stringa di connessione da L"(local)" in L"(local)\\nome", dove nome rappresenta l'istanza denominata. Per impostazione predefinita, SQL Server Express viene installato in un'istanza denominata. Verificare che nella variabile di ambiente INCLUDE sia presente la directory che contiene msoledbsql.h.
Eseguire il terzo elenco codici (Transact-SQL) per eliminare la stored procedure usata dall'applicazione.
if exists (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[fn_RectangleArea]'))
drop function fn_RectangleArea
go
CREATE FUNCTION fn_RectangleArea
(@Width int,
@Height int )
RETURNS int
AS
BEGIN
RETURN ( @Width * @Height )
END
GO
// compile with: ole32.lib oleaut32.lib
#include <iostream>
#include <atlbase.h> // CComPtr
#include "msoledbsql.h"
HRESULT InitializeAndEstablishConnection(CComPtr<IDBInitialize>& pIDBInitialize);
HRESULT ExecuteFunction(const CComPtr<IDBInitialize>& pIDBInitialize);
int main()
{
HRESULT hr = S_OK;
// Initialize the COM library.
CoInitialize(nullptr);
// All interfaces must be freed before CoUninitialize is called,
// thus limiting the scope of pIDBInitialize
{
CComPtr<IDBInitialize> pIDBInitialize;
// All the initialization stuff in a separate function.
hr = InitializeAndEstablishConnection(pIDBInitialize);
if (FAILED(hr))
{
std::cout << "Failed to connect\n";
goto EXIT;
}
hr = ExecuteFunction(pIDBInitialize);
if (FAILED(hr))
{
std::cout << "Failed in executing function\n";
goto EXIT;
}
if (FAILED(pIDBInitialize->Uninitialize()))
{
// Uninitialize is not required, but it fails if an interface
// has not been released. This can be used for debugging.
std::cout << "Problem uninitializing\n";
}
}
EXIT:
CoUninitialize();
return (FAILED(hr));
}
HRESULT InitializeAndEstablishConnection(CComPtr<IDBInitialize>& pIDBInitialize)
{
HRESULT hr = S_OK;
// Obtain access to the OLE DB Driver for SQL Server.
hr = CoCreateInstance(CLSID_MSOLEDBSQL,
nullptr,
CLSCTX_INPROC_SERVER,
IID_IDBInitialize,
reinterpret_cast<LPVOID *>(&pIDBInitialize));
if (FAILED(hr))
{
std::cout << "Failed in CoCreateInstance()\n";
return hr;
}
const ULONG nInitProps1 = 3;
const ULONG nInitProps2 = 1;
const ULONG nPropSets = 2;
CComBSTR server(L"(local)");
CComBSTR database(L"oledbtest");
CComBSTR auth(L"SSPI");
CComBSTR encrypt(L"Mandatory");
DBPROP InitProperties1[nInitProps1] = {};
DBPROP InitProperties2[nInitProps2] = {};
DBPROPSET rgInitPropSet[nPropSets] = {};
// Initialize the property values needed to establish the connection.
for (ULONG i = 0; i < nInitProps1; i++)
VariantInit(&InitProperties1[i].vValue);
// Specify server name.
InitProperties1[0].dwPropertyID = DBPROP_INIT_DATASOURCE;
InitProperties1[0].vValue.vt = VT_BSTR;
// Replace "MySqlServer" with proper value.
InitProperties1[0].vValue.bstrVal = server;
InitProperties1[0].dwOptions = DBPROPOPTIONS_REQUIRED;
InitProperties1[0].colid = DB_NULLID;
// Specify database name.
InitProperties1[1].dwPropertyID = DBPROP_INIT_CATALOG;
InitProperties1[1].vValue.vt = VT_BSTR;
InitProperties1[1].vValue.bstrVal = database;
InitProperties1[1].dwOptions = DBPROPOPTIONS_REQUIRED;
InitProperties1[1].colid = DB_NULLID;
InitProperties1[2].dwPropertyID = DBPROP_AUTH_INTEGRATED;
InitProperties1[2].vValue.vt = VT_BSTR;
InitProperties1[2].vValue.bstrVal = auth;
InitProperties1[2].dwOptions = DBPROPOPTIONS_REQUIRED;
InitProperties1[2].colid = DB_NULLID;
// Data should be encrypted before sending it over the network
VariantInit(&InitProperties2[0].vValue);
InitProperties2[0].dwPropertyID = SSPROP_INIT_ENCRYPT;
InitProperties2[0].vValue.vt = VT_BSTR;
InitProperties2[0].vValue.bstrVal = encrypt;
InitProperties2[0].dwOptions = DBPROPOPTIONS_REQUIRED;
InitProperties2[0].colid = DB_NULLID;
// Now that properties are set, construct the DBPROPSET structure
// (rgInitPropSet). The DBPROPSET structure is used to pass an array
// of DBPROP structures (InitProperties) to SetProperties method.
rgInitPropSet[0].guidPropertySet = DBPROPSET_DBINIT;
rgInitPropSet[0].cProperties = nInitProps1;
rgInitPropSet[0].rgProperties = InitProperties1;
rgInitPropSet[1].guidPropertySet = DBPROPSET_SQLSERVERDBINIT;
rgInitPropSet[1].cProperties = nInitProps2;
rgInitPropSet[1].rgProperties = InitProperties2;
// Set initialization properties.
CComPtr<IDBProperties> pIDBProperties;
hr = pIDBInitialize->QueryInterface(IID_IDBProperties,
reinterpret_cast<LPVOID *>(&pIDBProperties));
if (FAILED(hr))
{
std::cout << "Failed to obtain IDBProperties interface.\n";
return hr;
}
hr = pIDBProperties->SetProperties(nPropSets, rgInitPropSet);
if (FAILED(hr)) {
std::cout << "Failed to set initialization properties\n";
return hr;
}
// Now we establish connection to the data source.
if (FAILED(hr = pIDBInitialize->Initialize())) {
std::cout << "Problem in initializing\n";
}
return hr;
}
HRESULT ExecuteFunction(const CComPtr<IDBInitialize>& pIDBInitialize)
{
HRESULT hr = S_OK;
CComPtr<IDBCreateSession> pIDBCreateSession;
// Let us create a new session from the data source object.
if (FAILED(hr = pIDBInitialize->QueryInterface(IID_IDBCreateSession,
reinterpret_cast<LPVOID *>(&pIDBCreateSession))))
{
std::cout << "Failed to access IDBCreateSession interface\n";
return hr;
}
CComPtr<IDBCreateCommand> pIDBCreateCommand;
if (FAILED(hr = pIDBCreateSession->CreateSession(NULL,
IID_IDBCreateCommand,
reinterpret_cast<IUnknown **>(&pIDBCreateCommand))))
{
std::cout << "Failed to obtain IDBCreateCommand interface\n";
return hr;
}
// Create a Command
CComPtr<ICommandText> pICommandText;
if (FAILED(hr = pIDBCreateCommand->CreateCommand(NULL,
IID_ICommandText,
reinterpret_cast<IUnknown **>(&pICommandText))))
{
std::cout << "Failed to access ICommand interface\n";
return hr;
}
// The following buffer is used to store parameter values.
typedef struct tagSPROCPARAMS
{
long lReturnValue;
long inParam1;
long inParam2;
} SPROCPARAMS;
// Set the command text.
if (FAILED(hr = pICommandText->SetCommandText(DBGUID_DBSQL, L"{? = CALL fn_RectangleArea(?, ?) }")))
{
std::cout << "Failed to set command text\n";
return hr;
}
// Set the parameters information.
CComPtr<ICommandWithParameters> pICommandWithParams;
if (FAILED(hr = pICommandText->QueryInterface(IID_ICommandWithParameters,
reinterpret_cast<LPVOID *>(&pICommandWithParams))))
{
std::cout << "Failed to obtain ICommandWithParameters\n";
return hr;
}
const ULONG nParams = 3; // No. of parameters in the command
DBPARAMBINDINFO ParamBindInfo[nParams] = {};
DB_UPARAMS ParamOrdinals[nParams] = {};
DBROWCOUNT cNumRows = 0;
// Describe the command parameters (parameter name, provider specific name
// of the parameter's data type etc.) in an array of DBPARAMBINDINFO
// structures. This information is then used by SetParameterInfo().
ParamBindInfo[0].pwszDataSourceType = const_cast<LPOLESTR>(L"DBTYPE_I4");
ParamBindInfo[0].pwszName = NULL;
ParamBindInfo[0].ulParamSize = sizeof(long);
ParamBindInfo[0].dwFlags = DBPARAMFLAGS_ISOUTPUT;
ParamBindInfo[0].bPrecision = 11;
ParamBindInfo[0].bScale = 0;
ParamOrdinals[0] = 1;
ParamBindInfo[1].pwszDataSourceType = const_cast<LPOLESTR>(L"DBTYPE_I4");
ParamBindInfo[1].pwszName = NULL; // L"@inparam1";
ParamBindInfo[1].ulParamSize = sizeof(long);
ParamBindInfo[1].dwFlags = DBPARAMFLAGS_ISINPUT;
ParamBindInfo[1].bPrecision = 11;
ParamBindInfo[1].bScale = 0;
ParamOrdinals[1] = 2;
ParamBindInfo[2].pwszDataSourceType = const_cast<LPOLESTR>(L"DBTYPE_I4");
ParamBindInfo[2].pwszName = NULL; // L"@inparam2";
ParamBindInfo[2].ulParamSize = sizeof(long);
ParamBindInfo[2].dwFlags = DBPARAMFLAGS_ISINPUT;
ParamBindInfo[2].bPrecision = 11;
ParamBindInfo[2].bScale = 0;
ParamOrdinals[2] = 3;
if (FAILED(hr = pICommandWithParams->SetParameterInfo(nParams,
ParamOrdinals,
ParamBindInfo)))
{
std::cout << "Failed in setting parameter info.(SetParameterInfo)\n";
return hr;
}
HACCESSOR hAccessor = 0;
SPROCPARAMS sprocparams = {0,5,10};
// Declare array of DBBINDING structures, one for each parameter in the command
DBBINDING acDBBinding[nParams] = {};
// Describe the consumer buffer; initialize the array of DBBINDING structures.
// Each binding associates a single parameter to the consumer's buffer.
for (ULONG i = 0; i < nParams; i++)
{
acDBBinding[i].obLength = 0;
acDBBinding[i].obStatus = 0;
acDBBinding[i].pTypeInfo = NULL;
acDBBinding[i].pObject = NULL;
acDBBinding[i].pBindExt = NULL;
acDBBinding[i].dwPart = DBPART_VALUE;
acDBBinding[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
acDBBinding[i].dwFlags = 0;
acDBBinding[i].bScale = 0;
} // for
acDBBinding[0].iOrdinal = 1;
acDBBinding[0].obValue = offsetof(SPROCPARAMS, lReturnValue);
acDBBinding[0].eParamIO = DBPARAMIO_OUTPUT;
acDBBinding[0].cbMaxLen = sizeof(long);
acDBBinding[0].wType = DBTYPE_I4;
acDBBinding[0].bPrecision = 11;
acDBBinding[1].iOrdinal = 2;
acDBBinding[1].obValue = offsetof(SPROCPARAMS, inParam1);
acDBBinding[1].eParamIO = DBPARAMIO_INPUT;
acDBBinding[1].cbMaxLen = sizeof(long);
acDBBinding[1].wType = DBTYPE_I4;
acDBBinding[1].bPrecision = 11;
acDBBinding[2].iOrdinal = 3;
acDBBinding[2].obValue = offsetof(SPROCPARAMS, inParam2);
acDBBinding[2].eParamIO = DBPARAMIO_INPUT;
acDBBinding[2].cbMaxLen = sizeof(long);
acDBBinding[2].wType = DBTYPE_I4;
acDBBinding[2].bPrecision = 11;
// Let us create an accessor from the above set of bindings.
CComPtr<IAccessor> pIAccessor;
hr = pICommandWithParams->QueryInterface(IID_IAccessor,
reinterpret_cast<LPVOID *>(&pIAccessor));
if (FAILED(hr))
{
std::cout << "Failed to get IAccessor interface\n";
return hr;
}
DBBINDSTATUS acDBBindStatus[nParams] = {};
hr = pIAccessor->CreateAccessor(DBACCESSOR_PARAMETERDATA,
nParams,
acDBBinding,
sizeof(SPROCPARAMS),
&hAccessor,
acDBBindStatus);
if (FAILED(hr))
{
std::cout << "Failed to create accessor for the defined parameters\n";
return hr;
}
// Initialize DBPARAMS structure for command execution. DBPARAMS specifies the
// parameter values in the command. DBPARAMS is then passed to Execute.
DBPARAMS Params = {nullptr, 0, 0};
Params.pData = &sprocparams;
Params.cParamSets = 1;
Params.hAccessor = hAccessor;
// Execute the command.
if (SUCCEEDED(hr = pICommandText->Execute(nullptr,
IID_NULL,
&Params,
&cNumRows,
nullptr)))
{
printf("Return value = %d\n", sprocparams.lReturnValue);
}
else
{
std::cout << "Failed to execute command\n";
}
// Release memory.
pIAccessor->ReleaseAccessor(hAccessor, nullptr);
return hr;
}
drop function fn_RectangleArea
go
Vedere anche
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