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;
7 using System.Data.SqlClient;
8
9 namespace ASP.NETDemo
10 {
11
12 class SQLHelper
13 {
14 private static string connString = "Server=F-PC\\SQLEXPRESS;DataBase=StudentManageDB;Uid=sa;Pwd=123456";
15 /// <summary>
16 /// 返回单一结果查询
17 /// </summary>
18 /// <param name="sql"></param>
19 /// <returns></returns>
20 public static object GetSingleResult(string sql)
21 {
22 SqlConnection conn = new SqlConnection(connString);
23 conn.Open();
24 SqlCommand cmd = new SqlCommand(sql, conn);
25 object result = cmd.ExecuteScalar();
26 conn.Close();
27 return result;
28 }
29 /// <summary>
30 /// 增、删、改
31 /// </summary>
32 public static int Update(string sql)
33 {
34 SqlConnection conn= new SqlConnection(connString);
35 SqlCommand cmd = new SqlCommand(sql,conn);
36 conn.Open();
37 int result = cmd.ExecuteNonQuery();
38 conn.Close();
39 return result;
40
41 }
42 /// <summary>
43 /// 返回多个查询结果
44 /// </summary>
45 /// <param name="sql"></param>
46 /// <returns></returns>
47 public static SqlDataReader getReader(string sql)
48 {
49 SqlConnection conn = new SqlConnection(connString);
50 SqlCommand cmd = new SqlCommand(sql,conn);
51 conn.Open();
52 SqlDataReader objReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
53 //该参数能够保证从外部关闭DataReader时，与之关联的Connection对象将随之关联
54 return objReader;
55
56 }
57 }
58 }
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;
7 using System.Data.SqlClient;
8
9 namespace ASP.NETDemo
10 {
11 class Program
12 {
13 //static void Main(string[] args)
14 //{
15 // string sql = "Update Students set Birthday='1994-12-15' where StudentId=10007";
16 // int result = SQLHelper.Update(sql);
17 // Console.WriteLine(result);
18 // Console.ReadLine();
19 //}
20
21 static void Main(string[] args)
22 {
23 string sql = "Select StudentName from Students";
24 SqlDataReader objReader = SQLHelper.getReader(sql);
25 while (objReader.Read())
26 {
27 Console.WriteLine(objReader["StudentName"]);
28 }
29 objReader.Close();//关掉读取器（同时自动关闭关联的连接）
30 Console.ReadLine();
31 }
32 }
33 }
