Execute a User-Defined Function and Process Return Code (OLE DB)

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)

Download OLE DB driver

In this example, a user-defined function is executed, and the return code is printed. This sample is not supported on IA64.

This sample uses the oledbtest database as an example. Please substitute it with any SQL Server database you have.

Important

When possible, use Windows Authentication. If Windows Authentication is not available, prompt users to enter their credentials at run time. Avoid storing credentials in a file. If you must persist credentials, you should encrypt them with the Win32 crypto API.

Example

Execute the first ( Transact-SQL) code listing to create the stored procedure used by the application.

Compile with ole32.lib oleaut32.lib and execute the second (C++) code listing. This application connects to your computer's default SQL Server instance. On some Windows operating systems, you will need to change (localhost) or (local) to the name of your SQL Server instance. To connect to a named instance, change the connection string from L"(local)" to L"(local)\\name" , where name is the named instance. By default, SQL Server Express installs to a named instance. Make sure your INCLUDE environment variable includes the directory that contains msoledbsql.h.

Execute the third ( Transact-SQL) code listing to delete the stored procedure used by the application.

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  

See Also

Processing Results How-to Topics (OLE DB)