public void refresh(){
		PreparedStatement st;
		Integer rs;
		String query;
		query="DELETE FROM messages";
		try {
			st = conn.prepareStatement(query);
			rs = st.executeUpdate();
			st.close();
		} catch (SQLException e) {
			System.out.println(e.getMessage());
		}
		query="DELETE FROM friends";
		try {
			st = conn.prepareStatement(query);
			rs = st.executeUpdate();
			st.close();
		} catch (SQLException e) {
			System.out.println(e.getMessage());
		}
		query="DELETE FROM people";
		try {
			st = conn.prepareStatement(query);
			rs = st.executeUpdate();
			st.close();
		} catch (SQLException e) {
			System.out.println(e.getMessage());
		}
	}