完整的修改和删除

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

namespace ado练习题
{
    class Program
    {
        static void Main(string[] args)
        {
            SqlConnection conn = new SqlConnection("server=.;database=Data0425;user=sa;pwd=123;");
            SqlCommand cmd = conn.CreateCommand();

            while (true)
            {
                //1、查询显示
                cmd.CommandText = "select *from student";
                conn.Open();
                SqlDataReader dr = cmd.ExecuteReader();
                if (dr.HasRows)
                {
                    Console.WriteLine("=================学生信息展示==================");
                    while (dr.Read())
                    {
                        int age = DateTime.Now.Year - Convert.ToDateTime(dr["birthday"]).Year;
                        Console.WriteLine(dr["Code"] + "  " + dr["Name"] + "  " + (Convert.ToBoolean(dr["Sex"]) ? "男" : "女") + "  " + (Convert.ToDecimal(dr["Score"]).ToString("#.##")) + "  " + (Convert.ToDateTime(dr["birthday"]).ToString("yyyy年MM月dd日")) + "  " + age);
                    }
                }

                conn.Close();

                //2、请输入你想要做的操作（1：添加，2：删除，3：修改）：
                Console.Write("请输入你的操作（1=添加，2=修改，3=删除）：");
                string usesss = Console.ReadLine();
                if (usesss == "1")
                {
                    Console.Clear();
                    Console.WriteLine("可以添加！");
                }
                else if (usesss == "3")
                {
                    Console.Clear();
                    Console.WriteLine("可以删除！");
                }
                else if (usesss == "2")
                {
                    //3、提示用户操作是否成功，刷新数据，回到2等待用户操作
                    //========================================================================
                    bool HasStu = false;

                    while (true)
                    {
                        //1、接收用户输入进来的学生编号
                        Console.Write("请输入要修改的学生编号：");
                        string Scode = Console.ReadLine();

                        //2、判断有无此学生
                        cmd.CommandText = "select *from Student where code =‘" + Scode + "‘";
                        conn.Open();
                        SqlDataReader dr1 = cmd.ExecuteReader();
                        //3、有此学生，那么继续修改操作，如果没有，提示无此学生信心，无法修改
                        if (dr1.HasRows)
                        {
                            HasStu = true;
                        }
                        else
                        {
                            HasStu = false;
                        }
                        conn.Close();

                        if (HasStu)
                        {
                            Console.WriteLine("已查询到此学生信息，请进行修改：");
                            Console.Write("请输入更改后的学生姓名：");
                            string Sname = Console.ReadLine();
                            Console.Write("请输入更改后的学生性别：");
                            bool Ssex = Convert.ToBoolean(Console.ReadLine());
                            Console.Write("请输入更改后的学生生日：");
                            DateTime Sbirthday = Convert.ToDateTime(Console.ReadLine());
                            Console.Write("请输入更改后的学生成绩：");
                            decimal Sscore = Convert.ToDecimal(Console.ReadLine());

                            cmd.CommandText = "update student set [email protected],[email protected],[email protected],[email protected] where code = @Scode";
                            cmd.Parameters.Clear();
                            cmd.Parameters.Add("@Sname", Sname);
                            cmd.Parameters.Add("@Ssex", Ssex);
                            cmd.Parameters.Add("@Sbirthday", Sbirthday);
                            cmd.Parameters.Add("@Sscore", Sscore);
                            cmd.Parameters.Add("@Scode", Scode);

                            conn.Open();
                            cmd.ExecuteNonQuery();
                            Console.Clear();
                            Console.WriteLine("修改成功！");
                            conn.Close();
                            break;
                        }
                        else
                        {
                            Console.WriteLine("查无此学生，请重新输入！按任意键继续...");
                            Console.ReadKey();
                        }
                    }

                    //=========================================================================
                }
                else
                {
                    Console.WriteLine("输入有误！请重新输入！");
                }

            }

            Console.ReadKey();
        }
    }
}