操作数据库（增删改）

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using System.Data.SqlClient;
 7 
 8 namespace ConsoleApplication1
 9 {
10     class Program4
11     {
12         static void Main4(string[] args)
13         {
14             //用户输入要删除的数据主键值
15             Console.WriteLine("请输入要删除的代号：");
16             string code = Console.ReadLine();
17 
18             //判断该数据存不存在
19             SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");
20             SqlCommand cmd = conn.CreateCommand();
21             cmd.CommandText = "select * from Info where Code='"+code+"'";
22             conn.Open();
23             SqlDataReader dr = cmd.ExecuteReader();
24             
25 
26             if (dr.HasRows)
27             {
28                 //说明该数据存在
29                 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");
30                 int sc = Convert.ToInt32(Console.ReadLine());
31 
32                 if (sc == 1)
33                 {
34                     //删除
35                     dr.Close(); //关闭读取器
36 
37                     cmd.CommandText = "delete from Info where Code='"+code+"'";
38                     cmd.ExecuteNonQuery();
39                     Console.WriteLine("删除成功！");
40                     
41                 }
42                 else
43                 {
44                     //不删除
45                     dr.Read();
46 
47                     string sex = Convert.ToBoolean(dr[2])?"男":"女";
48                     string nation = MinZu(dr[3].ToString());
49 
50                     string str = "代号："+dr[0]+"	姓名："+dr[1]+"	性别："+sex+"	民族："+nation+"	生日："+dr[4];
51 
52                     Console.WriteLine(str);
53 
54 
55                 }
56             }
57             else
58             {
59                 //数据不存在
60                 Console.WriteLine("输入的代号错误！");
61             }
62 
63             conn.Close();
64             Console.ReadLine();
65         }
66 
67 
68         static string MinZu(string code)
69         {
70             string name="";
71             SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");
72             SqlCommand cmd = conn.CreateCommand();
73             cmd.CommandText = "select Name from Nation where Code = '" + code + "'";
74             conn.Open();
75             SqlDataReader dr = cmd.ExecuteReader();
76             if (dr.HasRows)
77             {
78                 dr.Read();
79                 name = dr[0].ToString();
80             }
81             conn.Close();
82 
83             return name;
84         }
85     }
86 }

添加

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using System.Data.SqlClient;
 7 
 8 namespace ConsoleApplication1
 9 {
10     class Program3
11     {
12         static void Main3(string[] args)
13         {
14             //让用户输入要添加的内容
15             Console.WriteLine("请输入要添加的代号：");
16             string code = Console.ReadLine();
17 
18             Console.WriteLine("请输入姓名：");
19             string name = Console.ReadLine();
20 
21             Console.WriteLine("请输入性别：");
22             bool sex = Console.ReadLine()=="男"?true:false;
23 
24             Console.WriteLine("请输入民族：");
25             string nation = Console.ReadLine();
26 
27             Console.WriteLine("请输入生日：");
28             string birthday = Console.ReadLine();
29 
30             string nationcode = "n001";
31 
32             //将民族名称转为名族代号
33             SqlConnection conn = new SqlConnection("server=.;database=mydb;user=sa;pwd=123");
34             SqlCommand cmd = conn.CreateCommand();
35             cmd.CommandText = "select Code from Nation where Name = '"+nation+"'";
36             conn.Open();
37             SqlDataReader dr = cmd.ExecuteReader();
38             if (dr.HasRows)
39             {
40                 dr.Read();
41                 nationcode = dr[0].ToString();
42             }
43             conn.Close();
44 
45             //往Info表添加数据
46             cmd.CommandText = "insert into Info values('"+code+"','"+name+"','"+sex+"','"+nationcode+"','"+birthday+"')";
47             conn.Open();
48             cmd.ExecuteNonQuery();
49             conn.Close();
50             Console.WriteLine("添加成功！");
51 
52             Console.ReadLine();
53         }
54     }
55 }