ADO.NET三个核心对象的简要说明

 SqlConnection //连接字符串

SqlCommand //执行sql命令的对象

DataReader //读取数据库中的记录

注意除了SqlConnection要记得关闭外 DataReader也要即使关闭，否则在下次使用未关闭的DataReader时候会出错。

示例代码如下：

1. class Program
2.     {
4.         /// <summary>
5.         /// 应用程序的入口
6.         /// </summary>
7.         /// <param name="args"></param>
8.         /// <returns></returns>
9.         static void Main(string[] args)
10.         {
11.             string connectionString = GetConnectString();
12.             string queryString = "select * from person where id = 2";
13.             //string queryString = "delete from person where id = 2;";
14.             using (SqlConnection connection = new SqlConnection(connectionString))
15.             {
16.                 SqlCommand command = connection.CreateCommand();
17.                 command.CommandText = queryString;
18.                 command.CommandType = CommandType.Text;
20.                 try
21.                 {
22.                     connection.Open();
23.                     //command.ExecuteNonQuery();//执行非查询命令
24.                     SqlDataReader reader = command.ExecuteReader()//读取数据命令;
25.                     while (reader.Read())
26.                     {
27.                         for (int i = 0; i < reader.FieldCount; i++)
28.                         {
29.                             Console.Write("{0}/t", reader[i]);
30.                         }
31.                         Console.WriteLine();
32.                     }
33.                     reader.Close();
34.                 }
35.                 catch (System.Exception ex)
36.                 {
37.                     Console.WriteLine(ex.Message);
38.                 }
39.             }
40.             Console.Read();
41.         }
42.         
43.         #region 连接字符串
44.         /// <summary>
45.         /// 连接字符串
46.         /// </summary>
47.         /// <returns></returns>
48.         public static string GetConnectString()
49.         {
50.             return "Data Source=(local);Initial Catalog=mytestdb;"
51.            + "Integrated Security=SSPI";
52.         }
53.         #endregion