第一个ADO.NET连接SQl server数据库

ado.net连接sql server2008本机数据库

1.只连接数据库，然后做简单查询

1  using (SqlConnection conn = new SqlConnection("Data Source=127.0.0.1; Initial Catalog=MyTest;User ID=sa;Password=123456"))
2             {
3                 conn.Open();
4                 using (SqlCommand cmd = conn.CreateCommand())
5                 {
6                     long i = (long)cmd.ExecuteScalar();//bigint→long
7                     MessageBox.Show(i.ToString());
8                 }
9             }

2.能完成一般的数据库连接，实现增删改查基本功能

 1 using System.Windows.Controls;
 2 using System.Windows.Data;
 3 using System.Windows.Documents;
 4 using System.Windows.Input;
 5 using System.Windows.Media;
 6 using System.Windows.Media.Imaging;
 7 using System.Windows.Navigation;
 8 using System.Windows.Shapes;
 9 using System.Data.SqlClient;
10 
11 namespace ADONET基础
12 {
13     /// <summary>
14     /// MainWindow.xaml 的交互逻辑
15     /// </summary>
16     public partial class MainWindow : Window
17     {
18         public MainWindow()
19         {
20             InitializeComponent();
21         }
22 
23         private void button1_Click(object sender, RoutedEventArgs e)
24         {
25             //IDisposible
26             //using(类型 d = new ....)
27             //{.....................}
28 
29             //SqlConnection为建立和数据库连接的对象
30             //using (SqlConnection conn = new SqlConnection(
31             //    "Data Source=127.0.0.1; Initial Catalog=MyTest;User ID=sa;Password=123456"))
32             //{
33             //    conn.Open();//打开连接
34             //    //通过连接创建一个向数据库发命令（Command）的对象SqlCommand
35             //    using (SqlCommand cmd = conn.CreateCommand())
36             //    {
37             //        //CommandText为要执行的SQL语句
38 
39             //        cmd.CommandText = "Insert into T_Student(Name,Age) values(‘元芳‘,2100)";
40             //        cmd.ExecuteNonQuery();//执行
41             //    }                
42             //}
43 
44             //ExecuteNonQuery一般用来执行Update、Delete、Insert语句
45 
46             using (SqlConnection conn = new SqlConnection("Data Source=127.0.0.1; Initial Catalog=MyTest;User ID=sa;Password=123456"))
47             {
48                 conn.Open();
49                 using (SqlCommand cmd = conn.CreateCommand())
50                 {
51                     //cmd.CommandText = "select count(*) from T_Student where Age<100";
52                     //int i =  (int)cmd.ExecuteScalar();
53                     //MessageBox.Show(i+"条数据");
54 
55                     //cmd.CommandText = "select ‘aaa‘";
56                     ////ExecuteScalar一般用来执行有且只有一行一列返回值的SQL语句
57                     //string s = (string)cmd.ExecuteScalar();
58                     //MessageBox.Show(s);
59 
60                     //获得自增字段的值
61                     //cmd.CommandText = "insert into T_Student(Name,Age) values(‘aaa‘,123) ;select @@identity";
62                    // cmd.CommandText = "insert into T_Student(Name,Age) output inserted.Id values(‘aaa‘,123) ";
63                     long i = (long)cmd.ExecuteScalar();//bigint→long
64                     MessageBox.Show(i.ToString());
65                 }
66             }
67 
68             //MessageBox.Show("执行完成");
69         }
70     }
71 }