Sqlce的數據庫連接以及創建

public static bool CreateDb()
  {
   try
   {
    SqlCeEngine engine = new SqlCeEngine("Data Source =Storage Card/CG.sdf ");
    engine.CreateDatabase();
    SqlCeConnection ssceconn = new SqlCeConnection("Data Source =Storage Card/CG.sdf ");
    ssceconn.Open();
    SqlCeCommand sqlCreateTable = ssceconn.CreateCommand();
    sqlCreateTable.CommandText = "CREATE TABLE ZYK(Id int IDENTITY(0,1) PRIMARY KEY,Title nvarchar(40), ISBN nvarchar(16),BookNum int,RDate nvarchar(10))";
    sqlCreateTable.ExecuteNonQuery();
    sqlCreateTable.CommandText = "CREATE TABLE YDK(Id int IDENTITY(0,1) PRIMARY KEY,ShuShang nvarchar(30), ISBN nvarchar(16),BookNum int,RDate datetime)";
    sqlCreateTable.ExecuteNonQuery();
    sqlCreateTable.CommandText = "Create index ISBN_Idx on ZYK(ISBN)";
    sqlCreateTable.ExecuteNonQuery();
    sqlCreateTable.CommandText = "Create index ISBN_Idx on YDK(ISBN)";
    sqlCreateTable.ExecuteNonQuery();
    ssceconn.Close();
    return true;
   }
   catch
   {
    return false;
   }

  }
  /// <summary>
  /// 獲取連接
  /// </summary>
  /// <returns></returns>
  public static void GetConn()
  {
   if (File.Exists("Storage Card/CG.sdf") == false)
   {
    Mc.CreateDb();
   }
   if (Mc.gConn == null)
   {
    Mc.gConn = new SqlCeConnection("Data Source =Storage Card/CG.sdf ");
    Mc.gConn.Open();
   }
  }