ado.net 完整修改删除，攻击防攻击

完整修改和删除：
当你输入了要删除的用户名，先提示有没有此条数据

先查

后删/后改
------------

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

namespace 完整删除_修改_攻击防攻击
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("请输入要删除的用户名：");
            string name = Console.ReadLine();

            SqlConnection conn = new SqlConnection("server=.;database=Data1128;user=sa;pwd=123");
            SqlCommand com = conn.CreateCommand();
            com.CommandText = "select *from Users where usename='"+name+"'";

            conn.Open();
            SqlDataReader dr=com.ExecuteReader();
            if (dr.HasRows)//如果查到此用户信息
            {
                Console.Write("是否删除该用户：（Y/N）");//如果有此条信息，那么需要进行删除判断
                string n = Console.ReadLine();//记录用户的操作
                if (n.ToUpper() == "Y")//判断用户操作，如果是Y，说明要删除
                {
                    conn.Close();
                    //下面的代码是真正删除此条数据
                    com.CommandText="delete from Users where usename='"+name+"'";
                    
                    int i = 0;
                    try
                    {
                        conn.Open();
                        i = com.ExecuteNonQuery();
                    }
                    catch
                    {
                        Console.WriteLine("连接服务器失败！！");
                    }
                    finally
                    {
                        conn.Close();
                    }
                    if (i > 0)//判断是否删除成功
                    {
                        Console.WriteLine("删除成功！");
                        com.CommandText = "select *from Users";//查询所有用户信息
                        conn.Open();
                        SqlDataReader dr1 = com.ExecuteReader();
                        if (dr1.HasRows)//判断是否有用户信息
                        {
                            while (dr1.Read())//判断是否有下一行，若有直接打印
                            {
                                Console.WriteLine(dr1["code"] + "	" + dr1["usename"] + "	" + dr1["password"] + "	" + dr1["nick"] + "	" + (Convert.ToBoolean(dr1["sex"]) ? "男" : "女") + "	" + dr1["nation"] + "	" + dr1["class"] + "	" + (Convert.ToDateTime(dr1["birthday"]).ToShortDateString()));
                            }
                        }
                        else//无用户信息
                        {
                            Console.WriteLine("无数据！！");
                        }
                        conn.Close();
                    }
                    else
                    {
                        Console.WriteLine("删除失败！");
                    }
                }
                else//用户选择不删除
                {
                    Console.WriteLine("删除操作取消！！");
                }
            }
            else//未查到用户信息
            {
                Console.WriteLine("用户名输入错误！！");
            }


            conn.Close();
            Console.ReadLine();

        }
    }
}

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

namespace update
{
    class Program
    {
        static void Main(string[] args)
        {
            bool has = false;//设置一中间变量判断用输入的数据是否存在，true表示存在，false不存在

            Console.Write("请输入要修改的用户名：");
            string name = Console.ReadLine();

            SqlConnection conn = new SqlConnection("server=.;database=Data1128;user=sa;pwd=123");
            SqlCommand com = conn.CreateCommand();
            com.CommandText = "select *from Users where usename='"+name+"'";

            conn.Open();
            SqlDataReader dr = com.ExecuteReader();
            if (dr.HasRows)//如果查到此用户信息
            {
                has = true;//将中间变量更改为true，证明有此条信息
                if(dr.Read())//输出修改前要修改的用户的信息
                {
                    Console.WriteLine(dr["code"]+"	"+dr["usename"]+"	"+dr["password"]+"	"+dr["nick"]+"	"+(Convert.ToBoolean(dr["sex"])?"男":"女")+"	"+dr["nation"]+"	"+dr["class"]+"	"+(Convert.ToDateTime(dr["birthday"]).ToShortDateString()));
                }
            }
            conn.Close();
            if (has)
            {
                Console.Write("已查到此用户信息，是否要修改？（Y/N）");
                string mm = Console.ReadLine(); //记录用户的操作
                if (mm.ToUpper() == "Y")//判断用户操作，如果是Y，说明要修改
                {
                    Console.Write("请输入要修改的密码：");
                    string pwd = Console.ReadLine();
                    Console.Write("请输入要修改的昵称：");
                    string nick = Console.ReadLine();
                    Console.Write("请输入要修改的性别：");
                    string sex = Console.ReadLine();
                    Console.Write("请输入要修改的生日：");
                    string bir = Console.ReadLine();
                    Console.Write("请输入要修改的民族：");
                    string nation = Console.ReadLine();
                    Console.Write("请输入要修改的班级：");
                    string cla = Console.ReadLine();
                    //防攻击
                    com.CommandText = "update Users set PASSWORD=@pwd,nick=@nick,sex=@sex,nation=@nation,class=@cla,birthday=@bir where usename=@name";
                    com.Parameters.Clear();
                    com.Parameters.AddWithValue("@pwd", pwd);
                    com.Parameters.AddWithValue("@nick", nick);
                    com.Parameters.AddWithValue("@sex", sex);
                    com.Parameters.AddWithValue("@nation", nation);
                    com.Parameters.AddWithValue("@cla", cla);
                    com.Parameters.AddWithValue("@name", name);
                    com.Parameters.AddWithValue("@bir", bir);

                    int i = 0;
                    try
                    {
                        conn.Open();
                        i = com.ExecuteNonQuery();
                    }
                    catch(Exception ex)
                    {
                        Console.WriteLine("未连接到服务器！
"+ex);
                    }
                    finally
                    {
                        conn.Close();
                    }
                    if (i > 0)
                    {
                        Console.WriteLine("修改成功！");
                        com.CommandText = "select code,usename,password,nick,sex,(select nationname from Nation where nationcode=Users.nation) as 民族,(select classname from Class where classcode=Users.class) as 班级,birthday from Users where usename='" + name + "'";
                        conn.Open();
                        SqlDataReader dr1 = com.ExecuteReader();
                        if(dr1.HasRows)
                        {
                            while (dr1.Read())//输出修改后用户的信息
                            {
                                Console.WriteLine(dr1["code"] + "	" + dr1["usename"] + "	" + dr1["password"] + "	" + dr1["nick"] + "	" + (Convert.ToBoolean(dr1["sex"]) ? "男" : "女") + "	" + dr1["民族"] + "	" + dr1["班级"] + "	" + (Convert.ToDateTime(dr1["birthday"]).ToShortDateString()));
                            }
                        }
                        conn.Close();
                    }
                    else
                    {
                        Console.WriteLine("修改失败！！");
                    }
                }
                else//用户选择不修改
                {
                    Console.WriteLine("取消修改！");
                }
            }
            else//未查到用户信息，判断has=false
            {
                Console.WriteLine("无此用户！！");
            }
            Console.ReadLine();

        }
    }
}