用于操作数据库的通用模块

在开发过程中有大量涉及到与数据库相关的操作，为了便于开发和维护，把这些操作封装成类，实现代码复用原则。

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

namespace CommonClass
{
    public class DBExecute
    {
        private static string strConn = System.Configuration.ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;

        /// <summary>
        /// 无返回值的数据库操作，如插入、删除等；
        /// </summary>
        /// <param name="strSQL"></param>
        /// <returns></returns>
        public static int ExecuteSql(string strSQL)
        {
            SqlConnection conn = new SqlConnection(strConn);
            SqlCommand cmd = new SqlCommand(strSQL, conn);

            try
            {
                conn.Open();        //打开数据库
                cmd.ExecuteNonQuery();  //执行无返回值的数据库操作
                return 0;
            }

            catch (SqlException e)
            {
                throw new Exception(e.Message); //抛出异常
            }
            finally
            {
                cmd.Dispose();  //释放该组件占用的资源
                conn.Close();   //每次操作完毕都要关闭连接
            }
        }

        /// <summary>
        /// 返回值为DataReader类型的操作
        /// </summary>
        /// <param name="strSQL"></param>
        /// <returns></returns>
        public static int ExecuteSqlReader(string strSQL)
        {
            SqlConnection conn = new SqlConnection(strConn);
            SqlCommand cmd = new SqlCommand(strSQL, conn);

            try
            {
                conn.Open();
                SqlDataReader sdr = cmd.ExecuteReader();
                if (sdr.Read())
                {
                    return 0;   //执行成功，返回 0
                }
                else