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 = ;
try
{
conn.Open();
i = com.ExecuteNonQuery();
}
catch
{
Console.WriteLine("连接服务器失败！！");
}
finally
{
conn.Close();
}
if (i > )//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"] + "\t" + dr1["usename"] + "\t" + dr1["password"] + "\t" + dr1["nick"] + "\t" + (Convert.ToBoolean(dr1["sex"]) ? "男" : "女") + "\t" + dr1["nation"] + "\t" + dr1["class"] + "\t" + (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"]+"\t"+dr["usename"]+"\t"+dr["password"]+"\t"+dr["nick"]+"\t"+(Convert.ToBoolean(dr["sex"])?"男":"女")+"\t"+dr["nation"]+"\t"+dr["class"]+"\t"+(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 = ;
try
{
conn.Open();
i = com.ExecuteNonQuery();
}
catch(Exception ex)
{
Console.WriteLine("未连接到服务器！\n"+ex);
}
finally
{
conn.Close();
}
if (i > )
{
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"] + "\t" + dr1["usename"] + "\t" + dr1["password"] + "\t" + dr1["nick"] + "\t" + (Convert.ToBoolean(dr1["sex"]) ? "男" : "女") + "\t" + dr1["民族"] + "\t" + dr1["班级"] + "\t" + (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(); }
}
}