ADO--数据访问技术

 1 static void Main(string[] args)
 2         {
 3             //创建连接字符串
 4             string constr = "Data Source=PENGYOUQIANG-PC;Initial Catalog=lianlian;Integrated Security=True";
 5             //创建连接对象
 6             using (SqlConnection con = new SqlConnection(constr))
 7             { 
 8                 //编写执行的SQL语句
 9                 string Sql = "select * from lianxi";
10                 //执行SQL语句
11                 using(SqlCommand comm=new SqlCommand(Sql,con))
12                 {
13                     //打开连接
14                     con.Open();
15                     using (SqlDataReader reader=comm.ExecuteReader())
16                     {
17                         //判断表中是否有数据
18                         if (reader.HasRows)
19                         {
20                             //一行一行读取数据
21                             while(reader.Read())
22                             {
23                                 Console.Write(reader.GetInt32(0)+"    ");
24                                 Console.Write(reader.GetString(1) + "    ");
25                                 Console.Write(reader.GetString(2) + "    ");
26                                 Console.Write(reader.GetString(3) + "    ");
27                                 //用GetXxxx方法来获取值，如果为NULL会报异常，此时需要手写代码来判断
28                                 //Console.WriteLine(reader.IsDBNull(4) ? "NULL" : reader.GetInt32(4));
29                                 Console.Write(reader.GetInt32(4));
30                                 Console.WriteLine();
31                             }
32                             Console.ReadKey();
33                         }
34                     }
35                 }
36             }
37         }