保存的資料來源物件

SQL Server Native Client OLE DB 提供者利用 IPersistFile 介面支援保存的資料來源物件。

範例

A. 保存資料來源初始化：

這個範例會示範一個函數，此函數會保存定義伺服器和資料庫的資料來源初始化屬性，以及使用 Windows 驗證模式來進行連接。伺服器名稱和資料庫名稱會在此函數的 pLocation 和 pDatasource 參數中接收。

HRESULT SetAndSaveInitProps
    (
    IDBInitialize* pIDBInitialize,
    WCHAR* pDataSource,
    WCHAR* pCatalog,
    BOOL bUseWinNTAuth
    )
    {
    const ULONG     nProps = 4;
    ULONG           nSSProps;
    ULONG           nPropSets;
    ULONG           nProp;
    IDBProperties*  pIDBProperties  = NULL;
    IPersistFile*   pIPersistFile   = NULL;
    DBPROP          aInitProps[nProps];
    DBPROP*         aSSInitProps    = NULL;
    DBPROPSET*      aInitPropSets   = NULL;
    HRESULT         hr;

        nSSProps = 0;
        nPropSets = 1;

    aInitPropSets = new DBPROPSET[nPropSets];

    // Initialize common property options.
    for (nProp = 0; nProp < nProps; nProp++)
        {
        VariantInit(&aInitProps[nProp].vValue);
        aInitProps[nProp].dwOptions = DBPROPOPTIONS_REQUIRED;
        aInitProps[nProp].colid = DB_NULLID;
        }

    // Level of prompting that will be done to complete the connection
    // process.
    aInitProps[0].dwPropertyID = DBPROP_INIT_PROMPT;
    aInitProps[0].vValue.vt = VT_I2;
    aInitProps[0].vValue.iVal = DBPROMPT_NOPROMPT;     

    // Server name.
    aInitProps[1].dwPropertyID = DBPROP_INIT_DATASOURCE;    
    aInitProps[1].vValue.vt = VT_BSTR;
    aInitProps[1].vValue.bstrVal = SysAllocString(pDataSource);

    // Database.
    aInitProps[2].dwPropertyID = DBPROP_INIT_CATALOG;
    aInitProps[2].vValue.vt = VT_BSTR;
    aInitProps[2].vValue.bstrVal = SysAllocString(pCatalog);

    aInitProps[3].dwPropertyID = DBPROP_AUTH_INTEGRATED;
    if (bUseWinNTAuth == TRUE)
    {
        aInitProps[3].vValue.vt = VT_BSTR;
        aInitProps[3].vValue.bstrVal = SysAllocString(L"SSPI");
    } //end if

    // Now that properties are set, construct the PropertySet array.
    aInitPropSets[0].guidPropertySet = DBPROPSET_DBINIT;
    aInitPropSets[0].cProperties = nProps;
    aInitPropSets[0].rgProperties = aInitProps;

    // Set initialization properties
    pIDBInitialize->QueryInterface(IID_IDBProperties,
        (void**) &pIDBProperties);
    hr = pIDBProperties->SetProperties(nPropSets, aInitPropSets);
    if (FAILED(hr))
        {
        // Display error from failed SetProperties.
        }
    pIDBProperties->Release();

    // Free references on OLE known strings.
    for (nProp = 0; nProp < nProps; nProp++)
        {
        if (aInitProps[nProp].vValue.vt == VT_BSTR)
            SysFreeString(aInitProps[nProp].vValue.bstrVal);
        }

    for (nProp = 0; nProp < nSSProps; nProp++)
        {
        if (aSSInitProps[nProp].vValue.vt == VT_BSTR)
            SysFreeString(aSSInitProps[nProp].vValue.bstrVal);
        }

    // Free dynamically allocated memory.
    delete [] aInitPropSets;
    delete [] aSSInitProps;

    // On success, persist the data source.
    if (SUCCEEDED(hr))
        {
        pIDBInitialize->QueryInterface(IID_IPersistFile,
            (void**) &pIPersistFile);

        hr = pIPersistFile->Save(OLESTR("MyDataSource.txt"), FALSE);

        if (FAILED(hr))
            {
            // Display errors from IPersistFile interface.
            }
        pIPersistFile->Release();
        }

    return (hr);
    }

B. 使用保存的資料來源初始化：

此範例會搭配其他初始化屬性來使用保存的資料來源物件，這些屬性會提供 SQL Server 登入和密碼。

HRESULT InitFromPersistedDS
    (
    IDBInitialize* pIDBInitialize,
    WCHAR* pPersistedDSN,
    WCHAR* pUID,
    WCHAR* pPWD
    )
    {
    //const ULONG   nProps = 3;
    const ULONG     nProps = 1;
    const ULONG     nPropSets = 1;
    ULONG           nProp;
    IDBProperties*  pIDBProperties  = NULL;
    IPersistFile*   pIPersistFile   = NULL;
    DBPROP          aInitProps[nProps];
    DBPROPSET       aInitPropSets[nPropSets];
    HRESULT         hr;

    // First load the persisted data source information.
    pIDBInitialize->QueryInterface(IID_IPersistFile,
        (void**) &pIPersistFile);

    hr = pIPersistFile->Load(pPersistedDSN, STGM_DIRECT);

    if (FAILED(hr))
        {
        // Display errors from IPersistFile interface.
        }
    pIPersistFile->Release();

    if (FAILED(hr))
        {
        return (hr);
        }

    // Initialize common property options.
    for (nProp = 0; nProp < nProps; nProp++)
        {
        VariantInit(&aInitProps[nProp].vValue);
        aInitProps[nProp].dwOptions = DBPROPOPTIONS_REQUIRED;
        aInitProps[nProp].colid = DB_NULLID;
        }

    // Level of prompting that will be done to complete the connection
    // process.
    aInitProps[0].dwPropertyID = DBPROP_INIT_PROMPT;
    aInitProps[0].vValue.vt = VT_I2;
    aInitProps[0].vValue.iVal = DBPROMPT_NOPROMPT;    

    // Now that properties are set, construct the PropertySet array.
    aInitPropSets[0].guidPropertySet = DBPROPSET_DBINIT;
    aInitPropSets[0].cProperties = nProps;
    aInitPropSets[0].rgProperties = aInitProps;

    // Set initialization properties
    pIDBInitialize->QueryInterface(IID_IDBProperties,
        (void**) &pIDBProperties);
    hr = pIDBProperties->SetProperties(nPropSets, aInitPropSets);
    if (SUCCEEDED(hr))
        {
        hr = pIDBInitialize->Initialize();
        if (FAILED(hr))
            {
            DumpError(pIDBInitialize, IID_IDBInitialize);
            }
        }
    else
        {
        // Display error from failed SetProperties.
        }
    pIDBProperties->Release();

    // Free references on OLE known strings.
    for (nProp = 0; nProp < nProps; nProp++)
        {
        if (aInitProps[nProp].vValue.vt == VT_BSTR)
            SysFreeString(aInitProps[nProp].vValue.bstrVal);
        }

    return (hr);
    }

IPersistFile::Save 方法可以在呼叫 IDBInitialize::Initialize 之前或之後呼叫。當從 IDBInitialize::Initialize 成功傳回之後呼叫此方法時，可確保已保存有效的資料來源規格。

請參閱

概念

資料來源物件 (OLE DB)