Ausführen einer benutzerdefinierten Funktion und Verarbeiten des Rückgabecodes (OLE DB)
Gilt für:
SQL Server Azure SQL-Datenbank Azure SQL verwaltete Instanz Azure Synapse Analytics Analytics Platform System (PDW)
In diesem Beispiel wird eine benutzerdefinierte Funktion ausgeführt, und der Rückgabecode wird ausgegeben. Dieses Beispiel wird nicht auf IA64-basierten Systemen unterstützt.
Für dieses Beispiel wird die Datenbank oledbtest als Beispiel verwendet. Ersetzen Sie es durch eine SQL Server-Datenbank, über die Sie verfügen.
Wichtig
Verwenden Sie nach Möglichkeit die Windows-Authentifizierung. Wenn die Windows-Authentifizierung nicht verfügbar ist, fordern Sie die Benutzer auf, ihre Anmeldeinformationen zur Laufzeit einzugeben. Die Anmeldeinformationen sollten nicht in einer Datei gespeichert werden. Wenn Sie die Anmeldeinformationen permanent speichern müssen, verschlüsseln Sie sie mit der Win32 Crypto-API.
Beispiel
Führen Sie das erste Codelisting (Transact-SQL) aus, um die von der Anwendung verwendete gespeicherte Prozedur zu erstellen.
Kompilieren Sie mit ole32.lib und oleaut32.lib, und führen Sie das zweite Codelisting (C++) aus. Diese Anwendung stellt eine Verbindung mit der SQL Server-Standardinstanz des Computers her. Bei einigen Windows-Betriebssystemen müssen Sie (localhost) oder (local) in den Namen der SQL Server -Instanz ändern. Ändern Sie zum Herstellen einer Verbindung mit einer benannten Instanz die Verbindungszeichenfolge von L"(local)" in L"(local)\\Name", wobei "Name" die benannte Instanz darstellt. Standardmäßig wird SQL Server Express in einer benannten Instanz installiert. Stellen Sie sicher, dass die INCLUDE-Umgebungsvariable das Verzeichnis einschließt, das „msoledbsql.h“ enthält.
Führen Sie das dritte Codelisting (Transact-SQL) aus, um die von der Anwendung verwendete gespeicherte Prozedur zu löschen.
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
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