ADO.NET—通用数据访问类的使用 

 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 }

 

posted @ 2017-07-14 09:17  一只羚  阅读(234)  评论(0)    收藏  举报