数据库操作 （数据操作类）

 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     //提供数据连接对象
11     public class DBConnect
12     {
13         private static string connstring = "server=.;database=mydb;user=sa;pwd=123";
14 
15         public static SqlConnection Conn
16         {
17             get {
18                 return new SqlConnection(connstring);
19             }
20         }
21     }
22 }

建立属性

1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace ConsoleApplication1
 8 {
 9     public class Nation
10     {
11         private string code;
12 
13         public string Code
14         {
15             get { return code; }
16             set { code = value; }
17         }
18         private string name;
19 
20         public string Name
21         {
22             get { return name; }
23             set { name = value; }
24         }
25     }
26 }
封装运算
 
 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     //主要实现对Nation表的各种操作（增删改查）
11     public class NationDA
12     {
13         private SqlConnection _conn; //连接对象
14         private SqlCommand _cmd; //命令对象
15         private SqlDataReader _dr; //读取器对象
16 
17         //构造方法来初始化连接对象 命令对象
18         public NationDA()
19         {
20             _conn = DBConnect.Conn; //对连接对象进行初始化
21             _cmd = _conn.CreateCommand(); //对命令对象进行初始化
22         }
23 
24         //添加数据的方法
25         public bool Add(string code,string name)
26         {
27             _cmd.CommandText = "insert into Nation values(@code,@name)";
28             _cmd.Parameters.AddWithValue("@code",code);
29             _cmd.Parameters.AddWithValue("@name",name);
30 
31             _conn.Open();
32             int n = _cmd.ExecuteNonQuery();
33             _conn.Close();
34 
35             if (n > 0)
36             {
37                 return true;
38             }
39             else
40             {
41                 return false;
42             }
43         }
44 
45         //查询所有数据的方法
46         public List<Nation> Select()
47         {
48             _cmd.CommandText = "select * from Nation";
49             _conn.Open();
50             _dr = _cmd.ExecuteReader();
51             _conn.Close();
52 
53             //定义一个空的集合
54             List<Nation> list = new List<Nation>();
55 
56             if (_dr.HasRows)
57             {
58                 while (_dr.Read())
59                 {
60                     //造一个Nation对象
61                     Nation data = new Nation();
62                     data.Code = _dr[0].ToString();
63                     data.Name = _dr[1].ToString();
64 
65                     //扔到集合里面
66                     list.Add(data);
67                 }
68             }
69 
70             return list;
71         }
72     }
73 }

主函数调用

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace ConsoleApplication1
 8 {
 9     class Program
10     {
11         static void Main(string[] args)
12         {
13             Console.WriteLine("请输入代号：");
14             string code = Console.ReadLine();
15 
16             Console.WriteLine("请输入名称：");
17             string name = Console.ReadLine();
18 
19             NationDA da = new NationDA();
20 
21             if (da.Add(code, name))
22             {
23                 Console.WriteLine("添加成功！");
24             }
25             else
26             {
27                 Console.WriteLine("添加失败！");
28             }
29 
30 
31             Console.ReadLine();
32         }
33     }
34 }