Usar los objetos de error de OLE DB (SQL Server Compact)
Cuando se producen errores durante la ejecución de una aplicación basada en SQL Server Compact 3.5, el proveedor OLE DB para SQL Server Compact 3.5 devuelve y almacena una matriz de objetos de error. Se puede obtener acceso a estos objetos mediante OLE DB de la forma habitual. El proveedor OLE DB para SQL Server Compact 3.5 devuelve errores para cada interfaz admitida por el proveedor. Para obtener más información, vea Interfaces OLE DB implementadas (SQL Server Compact). Para obtener información acerca del mecanismo general de recuperación de la información de error por parte de un cliente OLE DB, consulte la sección Microsoft OLE DB de la documentación del SDK de Microsoft Data Access Components (MDAC) en MSDN Library.
Ejemplos
En el siguiente ejemplo se muestra cómo recuperar los números de error específicos del proveedor cuando se utiliza el proveedor OLE DB para SQL Server Compact 3.5.
Nota
Para que esta aplicación de ejemplo se ejecute, el archivo sqlceoledb35.dll debe estar incluido en el Registro. El archivo sqlceoledb35.dll se puede incluir en el Registro en Windows desde una línea de comandos con la utilidad regsvr32.
Nota
CLSID_SQLSERVERCE es una macro definida en el archivo de encabezado OLEDB que se asigna a CLSID_SQLSERVERCE_3_5.
#include <windows.h>
#include <sqlce_oledb.h>
#include <sqlce_err.h>
#include <stdio.h>
/// <summary>
/// This function demonstrates a routine that can handle and display
/// errors from the OLE DB provider for SQL Server Compact 3.5. The
/// errors that occured on the current thread are displayed.
/// </summary>
HRESULT DisplayCurrentThreadErrors()
{
static TCHAR *sErrIErrorInfo = L"IErrorInfo interface";
static TCHAR *sErrIErrorRecords = L"IErrorRecords interface";
static TCHAR *sErrRecordCount = L"error record count";
static TCHAR *sErrInfo = L"ERRORINFO structure";
static TCHAR *sErrStandardInfo = L"standard error info";
static TCHAR *sErrDescription = L"standard error description";
static TCHAR *sErrNoSource = L"error source";
HRESULT hr = S_OK;
IErrorInfo *pIErrorInfo = NULL;
IErrorRecords *pIErrorRecords = NULL;
ERRORINFO errorInfo = { 0 };
IErrorInfo *pIErrorInfoRecord = NULL;
try
{
// This interface supports returning error information.
// Get the error object from the system for the current
// thread.
hr = GetErrorInfo(0, &pIErrorInfo);
if ( hr == S_FALSE )
{
wprintf(L"No error occured.\n");
return S_OK;
}
if(FAILED(hr) || NULL == pIErrorInfo)
throw sErrIErrorInfo;
// The error records are retrieved from the IIErrorRecords
// interface, which can be obtained from the IErrorInfo
// interface.
hr = pIErrorInfo->QueryInterface(IID_IErrorRecords,
(void **) &pIErrorRecords);
if ( FAILED(hr) || NULL == pIErrorRecords )
throw sErrIErrorRecords;
// The IErrorInfo interface is no longer required because
// we have the IErrorRecords interface, relase it.
pIErrorInfo->Release();
pIErrorInfo = NULL;
ULONG ulNumErrorRecs = 0;
// Determine the number of records in this error object
hr = pIErrorRecords->GetRecordCount(&ulNumErrorRecs);
if ( FAILED(hr) )
throw sErrRecordCount;
// Loop over each error record in the error object to display
// information about each error. Errors are returned.
for (DWORD dwErrorIndex = 0;
dwErrorIndex < ulNumErrorRecs;
dwErrorIndex++)
{
// Retrieve basic error information for this error.
hr = pIErrorRecords->GetBasicErrorInfo(dwErrorIndex,
&errorInfo);
if ( FAILED(hr) )
throw sErrInfo;
TCHAR szCLSID[64] = { 0 };
TCHAR szIID[64] = { 0 };
TCHAR szDISPID[64] = { 0 };
StringFromGUID2(errorInfo.clsid, (LPOLESTR)szCLSID,
sizeof(szCLSID));
StringFromGUID2(errorInfo.iid, (LPOLESTR)szIID,
sizeof(szIID));
wprintf(L"HRESULT = %lx\n", errorInfo.hrError);
wprintf(L"clsid = %s\n", szCLSID);
wprintf(L"iid = %s\n", szIID);
wprintf(L"dispid = %ld\n", errorInfo.dispid);
wprintf(L"Native Error Code = %lx\n", errorInfo.dwMinor);
// Retrieve standard error information for this error.
hr = pIErrorRecords->GetErrorInfo(dwErrorIndex, NULL,
&pIErrorInfoRecord);
if ( FAILED(hr) )
throw sErrStandardInfo;
BSTR bstrDescriptionOfError;
BSTR bstrSourceOfError;
// Get the description of the error.
hr = pIErrorInfoRecord->GetDescription(
&bstrDescriptionOfError);
if ( FAILED(hr) )
throw sErrDescription;
wprintf(L"Description = %s\n", bstrDescriptionOfError);
// Get the source of the error.
hr = pIErrorInfoRecord->GetSource(&bstrSourceOfError);
if ( FAILED(hr) )
throw sErrNoSource;
wprintf(L"Description = %s\n", bstrSourceOfError);
// This interface variable will be used the next time
// though this loop. In the last error case this interface
// is no longer needed so we must release it.
if(NULL != pIErrorInfoRecord)
pIErrorInfoRecord->Release();
pIErrorInfoRecord = NULL;
}
}
catch( TCHAR *szMsg )
{
wprintf(L"Failed to retrieve ");
wprintf(szMsg);
}
if( pIErrorInfoRecord )
pIErrorInfoRecord->Release();
if ( pIErrorInfo )
pIErrorInfo->Release();
if ( pIErrorRecords )
pIErrorRecords->Release();
return hr;
}
/// <summary>
/// This called will try to connect to a non existant
/// database to cause an error condition so that the call
/// to DisplayCurrentThreadError() has some errors to
/// display.
/// </summary>
/// <param="pIDBProperties">
/// IDBProperties interface that is used to set the properties on
/// for the Sql Compact engine object.
/// </param>
/// <param="pIDBInitialize">
/// Interface to the Sql Compact initialization object.
/// </param>
void CreateErrorCondition(IDBProperties *pIDBProperties,
IDBInitialize *pIDBInitialize)
{
HRESULT hr = S_OK;
DBPROP dbprop[1];
DBPROPSET dbpropset[1];
VariantInit(&dbprop[0].vValue);
// Initialize a property that uses name of database.
dbprop[0].dwPropertyID = DBPROP_INIT_DATASOURCE;
dbprop[0].dwOptions = DBPROPOPTIONS_REQUIRED;
dbprop[0].vValue.vt = VT_BSTR;
dbprop[0].vValue.bstrVal = SysAllocString(L"t@#$94.SC5");
// Initialize the property set.
dbpropset[0].guidPropertySet = DBPROPSET_DBINIT;
dbpropset[0].rgProperties = dbprop;
dbpropset[0].cProperties = sizeof(dbprop)/sizeof(dbprop[0]);
hr = pIDBProperties->SetProperties(
sizeof(dbpropset)/sizeof(dbpropset[0]),
dbpropset);
VariantClear(&dbprop[0].vValue);
if( FAILED(hr) )
return;
SysFreeString(dbprop[0].vValue.bstrVal);
// This call will fail because the db does not exit.
pIDBInitialize->Initialize();
}
/// <summary>
/// Application entry point initializes and cleans up the
/// needed interfaces and then calls the
/// DisplayCurrentThreadErrors() function to display error
/// information for the main application thread.
/// </summary>
void main()
{
HRESULT hr = S_OK;
IDBProperties *pIDBProperties = NULL;
ISupportErrorInfo *pISupportErrorInfo = NULL;
IDBInitialize *pIDBInitialize = NULL;
BOOL bComInitialized = FALSE;
try
{
hr = CoInitialize(NULL);
if ( FAILED(hr) )
{
wprintf(L"CoInitialize failed");
throw hr;
}
bComInitialized = TRUE;
// Retrieve the SQL Compact edition initialization interface.
hr = CoCreateInstance(CLSID_SQLSERVERCE,
0,
CLSCTX_INPROC_SERVER,
IID_IDBInitialize,
(void**)&pIDBInitialize);
if( FAILED(hr) || NULL == pIDBInitialize )
{
wprintf(L"Failed to retrieve IDBInitialize Interface");
throw hr;
}
// Retrieve the property interface, This interface will enable
// setting of specific propertes on the SQL Server Compact
// engine object.
hr = CoCreateInstance(CLSID_SQLSERVERCE,
0,
CLSCTX_INPROC_SERVER,
IID_IDBProperties,
(void**) &pIDBProperties);
if( FAILED(hr) || NULL == pIDBProperties )
{
wprintf(L"Failed to retrieve IDBProperties Interface");
throw hr;
}
hr = pIDBProperties->QueryInterface(IID_ISupportErrorInfo,
(void**)&pISupportErrorInfo);
if( FAILED(hr) || NULL == pISupportErrorInfo )
{
wprintf(L"Interface does not support ISupportErrorInfo");
throw hr;
}
// Create an error condition by trying to open a non existance
// datafile.
CreateErrorCondition(pIDBProperties, pIDBInitialize);
// Display errors that occured on the current (main) thread.
hr = DisplayCurrentThreadErrors();
if ( FAILED(hr) )
throw hr;
}
catch( HRESULT hr)
{
wprintf(L", Error Code: %lx\n", hr);
}
if ( pISupportErrorInfo )
pISupportErrorInfo->Release();
if ( pIDBProperties )
pIDBProperties->Release();
if ( pIDBInitialize )
pIDBInitialize->Release();
if ( bComInitialized )
CoUninitialize();
}
Vea también
Referencia
Referencia del proveedor OLE DB (SQL Server Compact)