ASP.NET:分享一个操作SQL Server数据库的工具类

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Web;
  5 using System.Collections;
  6 using System.Data.SqlClient;
  7 
  8 public class DatabaseHelper
  9 {
 10     private string connectionString = Constants.ConnectionURL;
 11     
 12     //隐藏构造器；
 13     private DatabaseHelper()
 14     {
 15     }
 16 
 17     private DatabaseHelper(string connectionString)
 18     {
 19         this.connectionString = connectionString;
 20     }
 21 
 22     //默认参数连接数据库；
 23     public SqlConnection GetConnection()
 24     {
 25         SqlConnection connection = new SqlConnection(this.connectionString);
 26         return connection;
 27     }
 28 
 29     //指定连接字符串连接数据库；
 30     public SqlConnection GetConnection(string connectionString)
 31     {
 32         SqlConnection connection = new SqlConnection(connectionString);
 33         return connection;
 34     }
 35 
 36     //执行SQL SELECT 查询语句,返回JSON格式的查询结果；
 37     public string Query(SqlConnection connection, string SQLstatement){
 38         string str = "[";
 39 
 40         connection.Open();
 41         SqlCommand command = connection.CreateCommand();
 42         command.CommandText = SQLstatement;
 43         SqlDataReader dataReader = command.ExecuteReader();
 44         int i = 0;
 45         ArrayList arrayList = new ArrayList();
 46         for (i = 0; i < dataReader.FieldCount; i++)
 47         {
 48             arrayList.Add(dataReader.GetName(i));
 49         }
 50         while (dataReader.Read())
 51         { 
 52             str += "{";
 53             for (i = 0; i < dataReader.FieldCount; i++)
 54             {
 55                 str += arrayList[i].ToString() + ":" + dataReader[i].ToString();
 56                 if (!(i == dataReader.FieldCount - 1))
 57                 {
 58                     str += ",";
 59                 }
 60             }
 61             str += "},";
 62         }
 63         dataReader.Close();
 64         connection.Close();
 65         int index = str.LastIndexOf(",");
 66         str = str.Remove(index);
 67         str += "]";
 68         return str;
 69     }
 70 
 71     //执行SQL INSERT语句；
 72     public void Insert(SqlConnection connection, string SQLstatement)
 73     {
 74         connection.Open();
 75         SqlCommand command = connection.CreateCommand();
 76         command.CommandText = SQLstatement;
 77         command.ExecuteNonQuery();
 78         connection.Close();
 79     }
 80 
 81     //执行SQL UPDATE语句；
 82     public void Update(SqlConnection connection, string SQLstatement)
 83     {
 84         connection.Open();
 85         SqlCommand command = connection.CreateCommand();
 86         command.CommandText = SQLstatement;
 87         command.ExecuteNonQuery();
 88         connection.Close();
 89     }
 90 
 91     //执行SQL DELETE语句；
 92     public void Delete(SqlConnection connection, string SQLstatement)
 93     {
 94         connection.Open();
 95         SqlCommand command = connection.CreateCommand();
 96         command.CommandText = SQLstatement;
 97         command.ExecuteNonQuery();
 98         connection.Close();
 99     }
100 
101     //返回默认参数的实例对象；
102     public static DatabaseHelper GetInstance()
103     {
104         return new DatabaseHelper();
105     }
106 
107     //返回指定参数的实例对象；
108     public static DatabaseHelper GetInstance(string connectionString)
109     {
110         return new DatabaseHelper(connectionString);
111     }
112 }