Work log records and work experience records

The company requires a report to be submitted once a week, but I usually travel a lot and can’t remember what I did after a week, so I read a book on learning PHP, studied it for a while, and made a small thing with only functions and no interface. Call it universal thinking-wwwsw.
Use your phone to jot it down while you’re in the car! !
This code is a code that is full of loopholes and does not consider any security. Rookies can learn from this.
When I open it on my mobile phone, I find that the pop-up window displays garbled characters. I don’t know how to solve it. I hope an expert can give me some advice. In fact, I still want to build a cache, but it works now, so forget it. If I don’t do it first, my code will have to be changed drastically. I don’t have the time, because I am engaged in hardware automation code development, so I have nothing to do. Get this php code.
The functions are lacking and the interface is poor. I hope someone can give me some advice!
Demo address: Because the code security is not high, it is not recommended for use and is for beginners to study.

-- phpMyAdmin SQL Dump
-- version 3.3.7
-- http://www.phpmyadmin.net
--
-- Host: localhost
-- Date generated: November 14, 2011 13 :47
-- Server version: 5.0.90
-- PHP version: 5.2.14

SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";


/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 /*! 40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;

--
-- Database: `ww log`
 --

--------------------------------------------------- ------------

--
-- Table structure `exlog`
--

CREATE TABLE IF NOT EXISTS `exlog` (
 `id` int(11) NOT NULL auto_increment ,
 `ph` varchar(1000) NOT NULL,
 `summary` varchar(2000) NOT NULL,
 `user` varchar(20) NOT NULL,
 PRIMARY KEY (`id`),
 KEY `id` (` id`),
 FULLTEXT KEY `ph` (`ph`),
 FULLTEXT KEY `summary` (`summary`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

--
-- dump table Data in `exlog`
--


----------------------------------- --------------------

--
-- Table structure `mylog`
--

CREATE TABLE IF NOT EXISTS `mylog` (
 `id ` int(11) NOT NULL auto_increment,
 `date` varchar(10) NOT NULL,
 `week` varchar(6) NOT NULL,
 `edlog` varchar(500) NOT NULL,
 `sumlog` varchar(10000) NOT NULL,
 `user` varchar(20) NOT NULL,
 PRIMARY KEY (`id`),
 KEY `user` (`user`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC AUTO_INCREMENT=1 ;

--
-- Dump the data in the table `mylog`
--


---------------------------------- --------------------------------

--
-- Table structure `ow`
--

CREATE TABLE IF NOT EXISTS `ow` (
 `id` int(11) NOT NULL auto_increment,
 `date` datetime NOT NULL,
 `oneword` varchar(500) NOT NULL,
 `user` varchar(20) NOT NULL,
 PRIMARY KEY (`id`),
 KEY `user` (`user`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

--
-- Dump the data in the table `ow`
--


-------------------------------------------------- ----------

--
-- Table structure `user`
--

CREATE TABLE IF NOT EXISTS `user` (
 `username` varchar(20) NOT NULL,
 ` password` varchar(100) NOT NULL,
 `nickname` varchar(10) NOT NULL,
 `desc_id` varchar(100) NOT NULL,
 KEY `username` (`username`),
 KEY `nickname` (`nickname `)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

--
-- Transfer the data in the table `user`
--