public void delete(String columnName, int id, String table){
        String sql = "DELETE FROM " + table + " WHERE " + columnName + " = " + id;
        try{
            stmt = conn.createStatement();
            rs = stmt.executeQuery(sql);
            System.out.println(rs.next());
        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
    }