C#与数据库链接---小练4--删除语句

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

namespace ConsoleApplication2
{
    class Shanchuyuju
    {
        public const string AB = "server=.;database=wo0505;uid=sa;pwd=123";
        public static void Main222(string[] args)
        {
            Show();
            Shanchu();
            Show();
            Console.ReadLine();
        }//主函数，进行各部分主要功能的调用
        public static void Show()
        {
            SqlConnection con = new SqlConnection(AB);
            con.Open();

            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "select * from Info";
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                string aa = dr["Code"].ToString();
                string bb = dr["Name"].ToString();
                string cc = ((bool)dr["Sex"]) ? "男" : "女";
                string dd = dr["Nation"].ToString();
                string ee = ((DateTime)dr["Birthday"]).ToString("yyyy年MM月dd日");
                Console.WriteLine(aa + " " + bb + " " + cc + " " + dd + " " + ee);
            }

            con.Close();
        }//显示所要删除数据的表中的所有数据
        public static void Shanchu()
        {
            Console.WriteLine("请输入要删除的数据行的编号：");
            string bianhao=Console.ReadLine();
            string yan = Yanz(bianhao);
            if (yan == "you")
            {
                Shan(bianhao);
                Console.WriteLine("已删除！");
            }
            else
            {
                Console.WriteLine("您输入的编号不存在，请重新输入！");
            }
        }//删除，输入要删除的一行数据的编号（或其他列名，可改）
        public static string Yanz(string b)
        {
            string ok = "you";
            SqlConnection con = new SqlConnection(AB);
            con.Open();

            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "select * from Info";
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                if (dr["Code"].ToString() == b)
                { ok = "you"; break; }
                else { ok = "bu"; }
            }

            con.Close();
            return ok;
        }//验证输入的要删除行数的编号是否已存在，
        public static void Shan(string bi)
        {
            SqlConnection con = new SqlConnection(AB);
            con.Open();

            SqlCommand cmd = new SqlCommand();
            cmd.Connection = con;
            cmd.CommandText = "delete from Family where InfoCode='"+bi+"'";
            cmd.ExecuteNonQuery();
            cmd.CommandText = "delete from Work where InfoCode='"+bi+"'";
            cmd.ExecuteNonQuery();
            cmd.CommandText = "delete from Info where Code='"+bi+"'";
            cmd.ExecuteNonQuery();

            con.Close();
        }
        //删除已存在的数据，并关注该行数据以主键为主的“其他表中的关联数据”也一并删除
    }//简单的删除数据表中的数据
}