asp.net Oracle数据库访问操作类

    /// <summary>
    /// 数据访问抽象基础类
    ///
    /// </summary>
public class DBBase
{

    //数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.       
    public static string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString1"].ToString();
    public DBBase()
    {
    }

    #region 检查用户名是否存在
    /// <summary>
    /// 检查用户名是否存在，存在返回true，不存在返回false
    /// </summary>
    /// <param name="strSql"></param>
    /// <returns></returns>
    public static bool Exists(string strSql)
    {

        using (OracleConnection connection = new OracleConnection(connectionString))
        {
            connection.Open();
            OracleCommand myCmd = new OracleCommand(strSql, connection);
            try
            { 
                object obj = myCmd.ExecuteScalar(); //返回结果的第一行一列
                myCmd.Parameters.Clear();
                if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                {
                    return false;
                }
                else
                {
                    return true;
                }          
            }
            catch (Exception ex)
             {
                 throw ex;
             }
       }
    }

    #endregion

    #region  执行简单SQL语句 返回影响的记录数

    /// <summary>
    /// 执行SQL语句，返回影响的记录数
    /// </summary>
    /// <param name="SQLString">SQL语句</param>
    /// <returns>影响的记录数</returns>
    public static int ExecuteSql(string SQLString)
    {

        OracleConnection connection = null;
        OracleCommand cmd = null;
        try
        {
            connection = new OracleConnection(connectionString);
            cmd = new OracleCommand(SQLString, connection);
            connection.Open();
            int rows = cmd.ExecuteNonQuery();
            return rows;
        }
        finally
        {
            if (cmd != null)
            {
                cmd.Dispose();
            }
            if (connection != null)
            {
                connection.Close();
                connection.Dispose();
            }
        }
    }
       #endregion

    #region   执行查询语句，返回SqlDataReader
    /// <summary>
    /// 执行查询语句，返回SqlDataReader ( 注意：调用该方法后，一定要对SqlDataReader进行Close )
    /// </summary>
    /// <param name="strSQL">查询语句</param>
    /// <returns>SqlDataReader</returns>
    public static OracleDataReader ExecuteReader(string strSQL)
    {
        OracleConnection connection = new OracleConnection(connectionString);
        OracleCommand cmd = new OracleCommand(strSQL, connection);
        try
        {
            connection.Open();
            OracleDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            return myReader;
        }
        catch (System.Data.OracleClient.OracleException e)
        {
            throw e;
        }
        finally
        {
            connection.Close();

        }
    }
    #endregion

    #region  执行SQL查询语句，返回