.NET数据库工厂模式简单实现

通过改变配置文件实现访问不同数据库的工厂模式。

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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 System.Data.Common;
public partial class DataBaseFactory : System.Web.UI.Page
{
    private DbConnection con;
    private DbCommand cmd;
    private DbProviderFactory provider;
    public DataBaseFactory()
    {
        string providerName = ConfigurationManager.ConnectionStrings[1].ProviderName;
        provider = DbProviderFactories.GetFactory(providerName);
        con = provider.CreateConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings[1].ConnectionString;
        cmd = provider.CreateCommand();
        cmd.Connection = con;
    }
   public DataTable getAlarmTable(string sql)
    {
        if (con != null)
        {
            try
            {
                DataSet ds = new DataSet();
                DbDataAdapter da = provider.CreateDataAdapter(sql, con);
                da.Fill(ds);
                da.Dispose();
                return ds.Tables[0];
            }
            catch (Exception e)
            {
                //2010.01.26  注释打印信息，添加Log日志。
                Program.WriteLog(e.Message.ToString());
                //Console.WriteLine(e.Message);
                return null;
            }
            finally
            {
                if (con!= null)
                {
                    con.Close();
                }
            }
        }
        else
        {
            Console.WriteLine(DateTime.Now.ToString() + " 没有连接到数据库");
            return null;
        }
    }   
}