sqlserver 数据库操作类

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

namespace Train.Model
{
    /// <summary>
    /// 数据库操作基类
    /// 实现对Sql数据库的各种操作
    /// 创建时间：2008-4-8
    /// </summary>
    public class DB
    {
        //获取Web.Config数据库连接字符串
        private readonly string SqlConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString.ToString();
        
        private SqlConnection conn;     // 创建SQL连接
        private SqlDataAdapter sda;     // 创建SQL数据适配器
        private SqlDataReader sdr;      // 创建SQL数据读取器
        private SqlCommand cmd;         // 创建SQL命令对象
        private SqlParameter param;     // 创建SQL参数
        private DataSet ds;             // 创建SQL数据集
        private DataView dv;            // 创建SQL视图

        /// <summary>

        /// 打开数据库连接
        /// </summary>
        public void Open()
        {
            #region
            conn = new SqlConnection(SqlConnectionString);
            conn.Open();
            #endregion
        }

        /// <summary>
        /// 关闭数据库连接
        /// </summary>
        public void Close()
        {
            #region
            if (conn != null)
            {
                conn.Close();
                conn.Dispose();
            }
            #endregion
        }
        /// <summary>
        /// 返回数据库连接
        /// </summary>
        /// <returns>
        /// conn 成功返回
        /// </returns>
        public SqlConnection GetConn()