摘抄的一段使用ODBC API 连接数据库的代码 ps:msdn文档 http://msdn.microsoft.com/en-us/library/ms714562(VS.85).aspx头文件
  SQLHENV m_henv; /**////< ODBC环境句柄
 SQLHDBC m_hdbc; ///< ODBC句柄
SQLHSTMT m_hstmt; ///< ODBC游标句柄
 char m_szDSN[256]; /**////< 数据源名
char m_szUserName[256]; ///< 用户名
char m_szPassword[256]; ///< 密码
BOOL m_bAutoCommit; ///< 是否自动提交连接函数
 BOOL CODBCTestDemo001Dlg::AllocHandle(SQLHENV &henv, SQLHDBC &hdbc, SQLHSTMT &hstmt)
 {
SQLRETURN retcode;
retcode = SQLAllocHandle(SQL_HANDLE_ENV,SQL_NULL_HANDLE,&henv);
if(retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
  {
retcode = SQLSetEnvAttr(henv,SQL_ATTR_ODBC_VERSION,(void *)SQL_OV_ODBC3,0);
if(retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
{
retcode = SQLAllocHandle(SQL_HANDLE_DBC,henv,&hdbc);
if(retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
{
SQLSetConnectAttr(hdbc,(long)SQL_LOGIN_TIMEOUT,(void *)5,0);
if(m_bAutoCommit)
SQLSetConnectAttr(hdbc,(long)SQL_ATTR_AUTOCOMMIT,(void *)SQL_AUTOCOMMIT_ON,0);
else
SQLSetConnectAttr(hdbc,(long)SQL_ATTR_AUTOCOMMIT,(void *)SQL_AUTOCOMMIT_OFF,0);
retcode = SQLConnect(hdbc,(SQLCHAR *)(LPTSTR)m_szDSN,SQL_NTS,
(SQLCHAR *)(LPTSTR)m_szUserName,SQL_NTS,(SQLCHAR *)(LPTSTR)m_szPassword,SQL_NTS);
if(retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
{
return TRUE;
 }
else
{
//ShowError(SQL_HANDLE_DBC,hdbc);
}
SQLFreeHandle(SQL_HANDLE_DBC,hdbc);
hdbc = NULL;
}
else
TRACE("It's Useless!");
//ShowError(SQL_HANDLE_ENV,henv);
}
else
//ShowError(SQL_HANDLE_ENV,henv);
SQLFreeHandle(SQL_HANDLE_ENV,henv);
henv = NULL;
}
else
return FALSE;
return FALSE;
}关闭连接
void CODBCTestDemo001Dlg::DeAllocHandle(SQLHENV henv, SQLHDBC hdbc, SQLHSTMT hstmt)
{
if (m_hdbc)
{
SQLDisconnect(hdbc);
SQLFreeHandle(SQL_HANDLE_DBC,hdbc);
}
if (m_henv)
{
SQLFreeHandle(SQL_HANDLE_ENV,henv);
}
}
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