Objetos persistidos da fonte de dados
Aplica-se a: 
SQL Server Banco de Dados SQL do Azure Instância Gerenciada de SQL do Azure Azure Synapse Analytics Analytics Platform System (PDW)
O Driver do OLE DB para SQL Server é compatível com objetos persistidos da fonte de dados com a interface IPersistFile.
Exemplos
a. Inicialização de fonte de dados persistente:
Este exemplo mostra uma função que persiste as propriedades de inicialização de uma fonte de dados definindo um servidor, um banco de dados e o uso do Modo de Autenticação do Windows para conexão. O nome do servidor e o nome do banco de dados são recebidos nos parâmetros pLocation e pDatasource da função.
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. Uso de inicialização de fonte de dados persistida:
Este exemplo usa um objeto de fonte de dados persistido com propriedades de inicialização adicionais que fornecem um logon e uma senha do SQL Server.
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);
}
O método IPersistFile::Save pode ser chamado antes ou depois de chamar IDBInitialize::Initialize. A chamada do método após um retorno bem-sucedido de IDBInitialize::Initialize garante que uma especificação de fonte de dados válida seja persistida.