using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;namespace ConsoleApplication1{    class Program4    {        static void Main4(string[] args)        {            //用户输入要删除的数据主键值            Console.WriteLine("请输入要删除的代号：");            string code = Console.ReadLine();            //判断该数据存不存在            SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");            SqlCommand cmd = conn.CreateCommand();            cmd.CommandText = "select * from Info where Code='"+code+"'";            conn.Open();            SqlDataReader dr = cmd.ExecuteReader();                        if (dr.HasRows)            {                //说明该数据存在                Console.WriteLine("查到该数据，是否要执行删除操作，如果要删除请输入：1");                int sc = Convert.ToInt32(Console.ReadLine());                if (sc == 1)                {                    //删除                    dr.Close(); //关闭读取器                    cmd.CommandText = "delete from Info where Code='"+code+"'";                    cmd.ExecuteNonQuery();                    Console.WriteLine("删除成功！");                                    }                else                {                    //不删除                    dr.Read();                    string sex = Convert.ToBoolean(dr[2])?"男":"女";                    string nation = MinZu(dr[3].ToString());                    string str = "代号："+dr[0]+"\t姓名："+dr[1]+"\t性别："+sex+"\t民族："+nation+"\t生日："+dr[4];                    Console.WriteLine(str);                }            }            else            {                //数据不存在                Console.WriteLine("输入的代号错误！");            }            conn.Close();            Console.ReadLine();        }        static string MinZu(string code)        {            string name="";            SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");            SqlCommand cmd = conn.CreateCommand();            cmd.CommandText = "select Name from Nation where Code = '" + code + "'";            conn.Open();            SqlDataReader dr = cmd.ExecuteReader();            if (dr.HasRows)            {                dr.Read();                name = dr[0].ToString();            }            conn.Close();            return name;        }    }}

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;namespace ConsoleApplication1{    class Program3    {        static void Main3(string[] args)        {            //让用户输入要添加的内容            Console.WriteLine("请输入要添加的代号：");            string code = Console.ReadLine();            Console.WriteLine("请输入姓名：");            string name = Console.ReadLine();            Console.WriteLine("请输入性别：");            bool sex = Console.ReadLine()=="男"?true:false;            Console.WriteLine("请输入民族：");            string nation = Console.ReadLine();            Console.WriteLine("请输入生日：");            string birthday = Console.ReadLine();            string nationcode = "n001";            //将民族名称转为名族代号            SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");            SqlCommand cmd = conn.CreateCommand();            cmd.CommandText = "select Code from Nation where Name = '"+nation+"'";            conn.Open();            SqlDataReader dr = cmd.ExecuteReader();            if (dr.HasRows)            {                dr.Read();                nationcode = dr[0].ToString();            }            conn.Close();            //往Info表添加数据            cmd.CommandText = "insert into Info values('"+code+"','"+name+"','"+sex+"','"+nationcode+"','"+birthday+"')";            conn.Open();            cmd.ExecuteNonQuery();            conn.Close();            Console.WriteLine("添加成功！");            Console.ReadLine();        }    }}