<转>vc 用ado访问Oracle数据库的代码示例

#pragma once

class CDBOp
{
public:
	bool ReConnect();
	bool CloseConnect();
	bool OpenConnect(CString hostName, CString dBName, CString userName, CString password);
	bool GetItemData(CString itemID, float &price, CString &descript);  //取存储过程数据，这里只是举例说明
	CString GetErrorMsg();
	CDBOp();
	virtual ~CDBOp();
private:
	_ConnectionPtr m_pConnection;  //连接对象
	_RecordsetPtr m_pRecordset;     //记录集对象
	bool   m_bConnectSuccess;     //连接是否成功
	CString   m_strConnString;      //数据库连接字符串
	CString   m_strErrMsg;           //保存错误信息
};

#include "StdAfx.h"
#include "DBOp.h"

//类实现

CDBOp::CDBOp():m_bConnectSuccess(false)
{
	::CoInitialize(NULL);
	m_pConnection.CreateInstance("ADODB.Connection");
	m_pConnection->ConnectionTimeout=30;
	m_pRecordset.CreateInstance("ADODB.Recordset");
}
CDBOp::~CDBOp()
{
	//::CoUninitialize();
	CloseConnect();
}
//打开连接(数据库类型，主机名，数据库名，登陆名，密码)
//数据库类型: 0 为Sql server, 1为 Oracle
bool CDBOp::OpenConnect(
						CString hostName,
						CString dBName,
						CString userName,
						CString password)
{
	CString strConn;

	//MSDAORA or OraOLEDB.Oracle.1
	strConn = "Provider=OraOLEDB.Oracle.1";
	strConn+= ";Persist Security Info=true";
	strConn+= ";User ID=";
	strConn+= userName;
	strConn+= ";Password=";
	strConn+= password;
	strConn+= ";Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)";
	strConn+= "(HOST=";
	strConn+= hostName;
	strConn+= ")(PORT=1521))(CONNECT_DATA=";
	strConn+= "(SERVICE_NAME=";
	strConn+= dBName;
	strConn+= ")))";

	if (strConn.IsEmpty())
	{
		m_strErrMsg="The connect string is null.";
		return false;
	}
	CloseConnect();
	m_strConnString =strConn; 

	return ReConnect();
}
//再次连接
bool CDBOp::ReConnect()
{
	m_strErrMsg=_T("");
	m_bConnectSuccess= false;
	HRESULT hr;
	try
	{
		hr = m_pConnection->Open(_bstr_t(m_strConnString), "", "", adModeUnknown);
		if (SUCCEEDED(hr))
			m_bConnectSuccess=true;
	}
	catch(_com_error e)
	{
		m_strErrMsg.Format(_T("Connect database failure!\r\n\r\n message error:%s\r\n\r\n The connect string:%s"),e.ErrorMessage(),m_strConnString);
	}
	return m_bConnectSuccess;
}
//关闭链接
bool CDBOp::CloseConnect()
{
	if (m_bConnectSuccess)
	{
		if (m_pConnection->State==1)
			m_pConnection->Close();
		m_bConnectSuccess =false;
	}
	return true;
}
//取得错误信息
CString CDBOp::GetErrorMsg()
{
	return m_strErrMsg;
}

bool CDBOp::GetItemData(CString itemID, float &price, CString &descript)
{
	_CommandPtr   pCommand = NULL;
	pCommand.CreateInstance("ADODB.Command");
#ifdef   _DEBUG
	if   (pCommand   ==   NULL)
	{
		AfxMessageBox(_T("Command Created fail! Please confirm whether initialize COM."));
	}
#endif
	ASSERT(pCommand   !=   NULL);
	try
	{
		if (m_bConnectSuccess==false)
		{
			if (ReConnect()==false)
				return false;
		}
		//输入参数   itemID
		_ParameterPtr   pParamItemID;
		pParamItemID.CreateInstance("ADODB.Parameter");
		pParamItemID->Name="ItemID";   //所用存储过程参数名称
		pParamItemID->Type=adChar;    //参数类型
		pParamItemID->Size=10;     //参数大小
		pParamItemID->Direction=adParamInput;  //表明是输入参数
		pParamItemID->Value=_variant_t(itemID);
		pCommand->Parameters->Append(pParamItemID);    

		//输出参数   price
		_ParameterPtr   pParamPrice;
		pParamPrice.CreateInstance("ADODB.Parameter");
		pParamPrice->Name="Price";    //参数名称
		pParamPrice->Type=adNumeric;    //参数类型
		pParamPrice->Size=9;      //参数大小
		pParamPrice->Precision =9;
		pParamPrice->NumericScale =2;
		pParamPrice->Direction=adParamOutput;  //声明是输出参数
		pCommand->Parameters->Append(pParamPrice);  

		//输出参数   Descript
		_ParameterPtr   pParamDescript;
		pParamDescript.CreateInstance("ADODB.Parameter");
		pParamDescript->Name="Descript";   //参数名称
		pParamDescript->Type=adVarChar;    //参数类型
		pParamDescript->Size=160;     //参数大小
		pParamDescript->Direction=adParamOutput; //声明是输出参数
		pCommand->Parameters->Append(pParamDescript);
		//执行存储过程
		pCommand->ActiveConnection=m_pConnection;
		pCommand->CommandText="spItemInfo";   //存储过程名称
		pCommand->CommandType=adCmdStoredProc;  //表示为存储过程adCmdStoredProc
		pCommand->Execute(NULL,   NULL,   adCmdStoredProc);   

		price=(float)(pParamPrice->Value);
		descript = (char*)_bstr_t(pParamDescript->Value);
		return true;
	}
	catch(_com_error   e)
	{
		m_strErrMsg.Format(_T("Error:GetItemData. Reason:%s\n file: %s; line: %d\n"), e.ErrorMessage(), __FILE__, __LINE__);
		return false;
	}   

}

　　转自http://www.cnblogs.com/finema/archive/2008/08/22/1273478.html