使用 OLE DB 错误对象 (SQL Server Compact)
在执行基于 SQL Server Compact 4.0 的应用程序期间发生错误时，OLE DB Provider for SQL Server Compact 4.0 将返回并存储一组错误对象。然后，可以用通常的方式使用 OLE DB 来访问这些对象。OLE DB Provider for SQL Server Compact 可以返回提供程序支持的每个接口的错误。有关更多信息，请参阅实现的 OLE DB 接口 (SQL Server Compact)。有关 OLE DB 客户端检索错误信息的常规机制的信息，请参阅 MSDN Library 中 Microsoft 数据访问组件 (MDAC) SDK 文档的 Microsoft OLE DB 部分。
示例
下面的示例说明如何在使用 OLE DB Provider for SQL Server Compact 时检索提供程序特定的错误号：
备注
若要运行此示例应用程序，必须注册 sqlceoledb35.dll。在 Windows 中，使用 regsvr32 实用工具从命令行即可注册 sqlceoledb35.dll。
备注
CLSID_SQLSERVERCE 是一个在 OLEDB 头文件中定义的宏，映射到 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();
}