做个C#的类

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Collections;

namespace DAL
{
/// <summary>
/// 数据库操作摘要
/// 定义:周龙
/// 2008/11/23
/// </summary>
public sealed class DBHelper
{
private static readonly string connectionStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;

/// <summary>
/// 执行SQL语句,并返回受影响的行数
/// </summary>
/// <param name="cmdText">命令文本</param>
/// <param name="cmdType">命令类型</param>
/// <param name="sqlParams">参数</param>
/// <returns>返回受影响的行数</returns>
public static int ExecuteNonQuery(string cmdText, Comman