c#做的登录系统 (oracle数据库连接)

【实例截图】

【核心代码】

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

namespace MessageManage
{
    class Operate
    {
       private static OracleConnection conn;
       private static OracleCommand cmd;
        private static OracleDataReader odr;

        //登陆判断
        internal bool LoginJudge(string ID,string PWD)
        {
             conn =  DB.OC();
            conn.Open();
            cmd = new OracleCommand("select * from 登陆 where ID='"   ID   "' and PWD = '"   PWD   "'", conn);
            if (cmd.ExecuteScalar() != null)
            {
                return true;
            }
            else
            {
                return false;
            }
            
        }

        //修改密码时密码是否与账号一致
        internal static bool PWDJudge(string PWD, string ID)
        {
            conn = DB.OC();
            conn.Open();
            cmd = new OracleCommand("select * from 登陆 where ID='"   ID   "'", conn);
            odr=cmd.ExecuteReader();
            Boolean abc = false;
            while (odr.Read())
            {
                if (odr.GetValue(1).ToString().Equals(PWD))
                {
                    abc = true;
                }
                else
                {
                    abc = false;
                }
            }
            return abc;

        }

        //修改密码时两次新密码是否一致
        internal static bool NewPWDJudge(string a, string b)
        {
            if (a.Equals(b))
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        //更新密码
        internal static void updatePWD(string PWD, string ID)
        {
            conn = DB.OC();
            conn.Open();
            cmd = new OracleCommand("update 登陆 set PWD='" PWD "' where ID='" ID "'", conn);
            cmd.ExecuteNonQuery();
        }

    }
}