OLE DB 打开会话 Prepare()错误 会是什么原因？

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bool CJoyDbCommand::Create(const ATL::CSession& sess, PCWSTR wszCommand)
{
m_commandText = wszCommand;

HRESULT hr;
//创建一个命令会话
hr = __super::Create(sess, wszCommand);
if(FAILED(hr))
{
JOY_LOG_DB("failed create command <%s>.", (PCSTR)GetCommandTextA());
return false;
}
//准备，Prepare中有一个默认值为0的参数，表示执行次数
hr = __super::Prepare();
......
......
}

class CJoyDbCommand : public
CCommand<CDynamicParameterAccessor, CRowset, CMultipleResults>
{........
我不太会用ole db 望大大们赐教

[刚刚凉]

用GetLastError()看看 是什么错误

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错误代码：E_FAIL

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解决方法：
http://support.microsoft.com/kb/235053/zh-cn
/* -------------- Adding this code prevents the error:
ULONG ulOrds[]={1};
DBPARAMBINDINFO ParamInfo[1];

ParamInfo[0].pwszDataSourceType = (unsigned short *) L"DBTYPE_I4";
ParamInfo[0].bPrecision = 10;
ParamInfo[0].bScale = 0;
ParamInfo[0].dwFlags = DBPARAMFLAGS_ISINPUT;
ParamInfo[0].pwszName = NULL;

ParamInfo[0].ulParamSize = sizeof(LONG);

hr = SetParameterInfo(1, ulOrds, ParamInfo);
----------------*/
hr = Prepare(); //// hr = E_FAIL without SetParameterInfo call
if (E_FAIL == hr)