/// <summary>
  /// 内部保护的数据库连接类
  /// </summary>
  protected abstract class Provider
  {
   //一个静态的连接接口;
   private static System.Data.IDbConnection conn;
   /// <summary>
   /// 构造方法，设为私有类型，是防止外部无效的引用;
   /// </summary>
   protected Provider()
   {
    System.Data.IDbCommand x=new System.Data.OleDb.OleDbCommand();
   }
   /// <summary>
   /// 返回数据库边接类型
   /// </summary>
   public static DBType Type
   {
    get
    {
     
     return Provider.m_DBType;
    }
    set
    {
     Provider.m_DBType=value;
    }
   }
   private static string m_ConnectionString;
   private static string m_ConnectionStringSetName;
   /// <summary>
   /// 数据库连接字符串设置名称
   /// </summary>
   public static string ConnectionSetName
   {
    set
    {
     Provider.m_ConnectionStringSetName=value;
    }
   }
   /// <summary>
   /// 数据库连接字符串
   /// </summary>
   public static string ConnectionString
   {
    set
    {
     Provider.m_ConnectionString=value;
    }
   }
   private static DBType m_DBType;
   
   /// <summary>
   /// 获得数据库连接接口
   /// </summary>
   /// <returns>返回一个连接</returns>
   public static System.Data.IDbConnection getConn()
   {
    string ConnStr="";
    try{
    //System.Threading.Thread.GetDomain().UnhandledException+=new UnhandledExceptionEventHandler(ThrowDBException);
     if(Provider.m_ConnectionString==""||Provider.m_ConnectionString==null)
     {
      if(Provider.m_ConnectionStringSetName.Trim()=="")
      {
       ConnStr=System.Configuration.ConfigurationSettings.AppSettings["DataBase.ConnectionString"];
      }
      else
      {
       ConnStr=System.Configuration.ConfigurationSettings.AppSettings[Provider.m_ConnectionStringSetName];
      }
      
     }
     else
     {
      ConnStr=Provider.m_ConnectionString;
     }
     if(ConnStr==null||ConnStr=="")
     {
      throw new JoyBaseDBException("连接字符串为空或者是null类型，请检查您的ConnectionString以及ConnectionSetName是否进行正确设置，或者阅读相关说明.");
     }
&nb