io Programmo 32/IOPROG_32.ISO/SOFT/SqlEval7/devtools/samples/sqldmo/cpp/Smartptr/Smartptr.cpp

C/C++ Source or Header | 1998-08-11 | 7.9 KB | 291 lines

// **********************************************************************
// Smartptr -    SQL-DMO smartpointer sample application uses
//                the built-in Visual C 5.0 _comp_ptr_t support.
//                If prefered, adapt to use CComPtr or CComQIPtr
//                (VC 5.0 and later)
//
//                the _com_error calls ->Release automatically when it
//                goes out of scope to clean itself up.
//                there is no need to call delete or release.
// **********************************************************************

#define STRICT                    // Strict type checking.
#define WIN32_LEAN_AND_MEAN        // Do not include the world.
#define INC_OLE2                // Include OLE/COM files

#include <windows.h>
#include <stdio.h>
#include <comdef.h>             // Compiler support for _bstr_t

// The #import statement is locale specific. Change the path to import
// from the locale specific .rll file installed.
#import "c:\mssql7\binn\resources\1033\sqldmo.rll" no_namespace

// **********************************************************************
// Function declarations.
// **********************************************************************
void    vDisplayError(_com_error & pCE);
BOOL    bSetDefaults(_SQLServerPtr & spSQLServer);
BOOL    bConnect(_SQLServerPtr & spSQLServer);
void    vDisconnect(_SQLServerPtr & spSQLServer);
void    vDoQuery(_SQLServerPtr & spSQLServer, LPCTSTR strQuery);
void    vDisplayResults(QueryResultsPtr & spQueryResults);

// **********************************************************************
// Macros.
// **********************************************************************
#define _MAX_COL        25
#define _MAX_COL_FMT    "%-25s "

#define _SERVER            "."     // Local server
#define _USER            "sa"
#define _PWD            ""
#define _QUERYSTMT        "SELECT LastName, FirstName, HireDate FROM " \
                        " Northwind.dbo.Employees"

// **********************************************************************
// main()
// **********************************************************************
void main(void)
{
    printf("\n\nSQL-DMO Smart Pointer Sample\n");


    HRESULT hr;
    if SUCCEEDED(hr = CoInitialize(NULL) )
    {
        // Use the interface appropriate for LPSQLDMOSERVER.
        try
        {
            _SQLServerPtr spSQLServer;

            if (SUCCEEDED(spSQLServer.CreateInstance(__uuidof(SQLServer))))
            {
                try
                {
                    if (TRUE == bSetDefaults(spSQLServer))
                    {
                        vDoQuery(spSQLServer, _QUERYSTMT);
                    }

                    // Because the spSQLServer was created in main, it
                    // will not go out of scope until the end of main.
                    //
                    // However, this is after the OleUninitilize is called
                    // and causes an error.
                    //
                    // For this special case, call the .Release to
                    // clean up the pointer and do the work.
                    spSQLServer.Release();
                }
                catch(_com_error pCE)
                {
                    vDisplayError(pCE);
                    spSQLServer.Release();     //    Free the interface.
                }
            }
            else
            {
                printf("\nUnable to create the SQLServer object.");
            }
        }
        catch(_com_error pCE)
        {
            vDisplayError(pCE);
        }

        CoUninitialize();
    }
    else
    {
        printf("\nCall to CoInitialize failed.");
    }

    printf("\n");

}

// **********************************************************************
// vDisplayError
//
// Display error information.
// **********************************************************************
void vDisplayError(_com_error & pCE)
{
    //    Assuming ANSI build at this time.
    printf( "\n%s Error: %ld\r\n"
            "%s\r\n"
            "%s\r\n",
            (char*)pCE.Source(),
                   pCE.Error(),
            (char*)pCE.Description(),
            (char*)pCE.ErrorMessage());
}

// **********************************************************************
// bSetDefaults
//
// Accepts the current address so the RefCount does not need to be
// touched. There is no reason to increment it on entry and then
// decrement it on exit, just to be doing it.
// **********************************************************************
BOOL bSetDefaults(_SQLServerPtr & spSQLServer)
{
    BOOL bRC = FALSE;

    printf("\nSetting SQL Server object properties.");

    try
    {
        spSQLServer->PutLoginTimeout(10);
        spSQLServer->PutApplicationName("SmartPointers");
        spSQLServer->PutHostName("Test");
        spSQLServer->PutNetPacketSize(1024);

        bRC = TRUE;
    }
    catch(_com_error pCE)
    {
        vDisplayError(pCE);
    }
    return bRC;
}


// **********************************************************************
// bConnect
//
// Connect to the SQL Server.
// **********************************************************************
BOOL bConnect(_SQLServerPtr & spSQLServer)
{
    BOOL bRC = FALSE;

    printf("\nAttempting to connect to %s as %s", _SERVER, _USER);

    try
    {
        spSQLServer->Connect(_SERVER, _USER, _PWD);

        bRC = TRUE;
    }
    catch(_com_error pCE)
    {
        vDisplayError(pCE);
    }
    return bRC;
}


// **********************************************************************
// vDisconnect
//
// Disconnect from the SQL Server.
// **********************************************************************
void vDisconnect(_SQLServerPtr & spSQLServer)
{
    printf("\nDisconnecting from %s", _SERVER);

    try
    {
        spSQLServer->Close();
    }
    catch(_com_error pCE)
    {
        vDisplayError(pCE);
    }
}

// **********************************************************************
// vDoQuery
//
// Execute query capturing generated result sets in a QueryResults
// object.
// **********************************************************************
void vDoQuery(_SQLServerPtr & spSQLServer, LPCTSTR strQuery)
{
    QueryResultsPtr spQueryResults;

    if (TRUE == bConnect(spSQLServer))
    {
        printf("\nExecuting %s\n", strQuery);

        try
        {
            spQueryResults = spSQLServer->ExecuteWithResults(strQuery);

            vDisplayResults(spQueryResults);
        }
        catch(_com_error pCE)
        {
            vDisplayError(pCE);
        }

        vDisconnect(spSQLServer);

    }
}

// **********************************************************************
// vDisplayResults
//
// Print result set(s) information and contents.
// **********************************************************************
void vDisplayResults(QueryResultsPtr & spQueryResults)
{
    long    lMaxColLen = 0;
    char    strDisplayData[_MAX_COL +1] = "";
    _bstr_t bstrColName;
    _bstr_t bstrRowInfo;

    try
    {
        // Loop through the results sets.
        for (long lSet = 1; lSet <= spQueryResults->GetResultSets(); lSet++)
        {
            spQueryResults->PutCurrentResultSet(lSet);
            printf("\n >>> Result set #%ld\n", lSet);

            // Print the column headers.
            for (long lCols = 1; lCols <= spQueryResults->GetColumns(); lCols++)
            {
                // You do not need to call SysFreeString when using the smart
                // BSTR pointer (_bstr_t). The copy operator of the _bstr_t
                // performs a free on any prior value and then handles the
                // new data, preventing a memory leak when used in this loop.
                //
                // For complete details, see the definition of the _bstr_t
                // copy coperator in COMUTIL.H.
                bstrColName = spQueryResults->GetColumnName(lCols);

                // Assuming ANSI build for sample so casting as char*.
                strncpy(strDisplayData, (char *)bstrColName, _MAX_COL);
                printf(_MAX_COL_FMT, strDisplayData);
            }

            printf("\n");

            // Display the data.
            for (long lRows = 1; lRows <= spQueryResults->GetRows(); lRows++)
            {
                for (long lCols = 1; lCols <= spQueryResults->GetColumns(); lCols++)
                {
                    bstrRowInfo = spQueryResults->GetColumnString(lRows, lCols);

                    strncpy(strDisplayData, (char *)bstrRowInfo, _MAX_COL);
                    printf(_MAX_COL_FMT, strDisplayData);
                }
                // End of row.
                printf("\n");
            }

            printf("\nRows processed (%ld)", spQueryResults->GetRows());

        } // End of FOR loop processing a result set.
    }
    catch(_com_error pCE)
    {
        vDisplayError(pCE);
    }
}