C#_DBHelper_SQL数据库操作类.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;
 1 public class DBHelper 2   { 3     static string connStr = "Workstation id = localhost;" + 4                "Integrated Security = SSPI;" +  5                 "Database = 数据库名字;";//填入SQL数据库的登录信息。 6  7     8     static SqlConnection conn = new SqlConnection(connStr); 9 10     public static SqlDataReader GetDataReader(string sql)//返回值是一个数组，可通过dr[0],dr[1]使用各字段的值11     {12       SqlConnection myConn = conn;13       SqlDataReader dr = null;14 15       try16       {17         if (myConn.State == ConnectionState.Closed)18         {19           myConn.Open();20         }21         SqlCommand cmd = new SqlCommand(sql, myConn);22        23         dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);24       }25       catch 26       {27         28         if (myConn.State == ConnectionState.Open)29         {30           myConn.Close();31         }32 33       }34       return dr;35     }36 37     public static bool ExecuteNonQuery(string sql) //对于 UPDATE、INSERT 和 DELETE 语句，返回值为该命令所影响的行数。对于所有其他类型的语句，返回值为 -1。如果发生回滚，返回值也为 -138     {39       int n = 0;40 41       try42       {43         if (conn.State == ConnectionState.Closed)44         {45           conn.Open();46         }47         SqlCommand cmd = new SqlCommand(sql, conn);48         n = cmd.ExecuteNonQuery();49         50       }51       catch52       {53         54         return false;55       }56       finally57       {58         if (conn.State == ConnectionState.Open)59         {60           conn.Close();61         }62       }63       return n > 0;64     }65 66     public static Object ExecuteScalar(string sql)//使用ExecuteScalar()，增删改查如果成功，会返回一个对象，否则会返回一个null；67     {68       Object ob = null;69 70       try71       {72         if (conn.State == ConnectionState.Closed)73         {74           conn.Open();75         }76         SqlCommand cmd = new SqlCommand(sql, conn);77         ob = cmd.ExecuteScalar();78       }79       catch80       {81         return null;82       }83       finally84       {85         if (conn.State == ConnectionState.Open)86         {87           conn.Close();88         }89       }90       return ob;91     }92   }93 }

原标题：C#_DBHelper_SQL数据库操作类.

关键词：C#