/// <summary>
/// 执行SQL语句，返回DataSet
/// </summary>
/// <param name="sql">SQL语句（为了Oracle上能够使用，表的别名前不要加AS）</param>
/// <returns>DataTable</returns>
public DataSet ExecuteDataSet(string sql)
{
try
{
return(_db.ExecuteDataSet(sql));
}
catch (Exception ex)
{
throw new Exception(string.Format("查询失败！\r\nSQL语句为：{0}。\r\n{1}", sql, ex.ToString()));
}
}
