public boolean Validate(String Vdate)
{
	boolean result=false;
	ResultSet rs=null;
	if(Vdate.indexOf("/")>-1)
	{
		Vdate=Vdate.split("/")[2]+Vdate.split("/")[0]+Vdate.split("/")[1];
	}
	
	try
	{
		String sql="select count(*) as num from corresponding where value_date='"+Vdate+"'";
		rs = DBConn.Conn().executeQuery(sql);
		while(rs.next())
		{
			if(!rs.getString("num").equals("0"))
			{
				System.out.println("this date has been checked!");
				result=true;
			}
		}
	}catch(Exception e)
	{
		e.printStackTrace();
	}finally {
		try {
			rs.close();
			DBConn.Conn().close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	return result;
}