asp.net DbProviderFactory的使用－示例

using System; 
using System.Data; 
using System.Configuration; 
using System.Web; 
using System.Web.Security; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Web.UI.WebControls.WebParts; 
using System.Web.UI.HtmlControls; 
using CrystalDecisions.CrystalReports.Engine; 
using CrystalDecisions.Shared; 
using System.Data.Common; 
/// <summary> 
/// OrderInfoConfiguration 的摘要说明 
/// </summary> 
public class OrderInfoConfiguration 
{ 
private const string connectionString=@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Program Files\TutorialSampleCodeProjects\xtreme.mdb"; 
private const string queryString="SELECT a.[Order Date] AS 订单时间,a.[Order ID] AS 订单号,b.[Last Name]+\" \"+b.[First Name] AS 员工姓名,c.[Customer Name] AS 客户姓名,d.[Product Name] AS 产品名 FROM Orders a,Employee b,Customer c,Product d ,[Orders Detail] e WHERE a.[Employee ID]=b.[Employee ID] AND a.[Customer ID]=c.[Customer ID] AND a.[Order ID]=e.[Order ID] AND e.[Product ID]=d.[Product ID]"; 
public static DataSet OrderInfoDataSet 
{ 
get 
{ 
DataSet dataSet = new DataSet(); 
DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OleDb"); //获取工厂 
DbConnection con = factory.CreateConnection();//创建连接 
con.ConnectionString = connectionString; 
DbCommand cmd = factory.CreateCommand();//创建命令 
cmd.CommandText = queryString; 
cmd.CommandType = CommandType.Text; 
cmd.Connection = con; 
DbDataAdapter dapter = factory.CreateDataAdapter();//创建适配器 
dapter.SelectCommand = cmd; 
dapter.Fill(dataSet);//填充 
return dataSet; 
} 
} 
public OrderInfoConfiguration() 
{ 
// 
// TODO: 在此处添加构造函数逻辑 
// 
} 
} 
 
DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OleDb"); //获取工厂 这句就可以获得一个工厂，用这个工厂就可发生产该数据提供程序的各种对象了。 
如果是连接 
SqlServer：DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.SqlClient"); 
Oracle:DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OracleClient"); 
ODBC:DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.Odbc"); 
使用了这个，要是想换个数据库，是不是很方便了呢？呵呵。