<?php
  $con = mysql_connect("localhost:3306","root","");

  if (!$con) {
    die('Could not connect: ' . mysql_error());
  }

  mysql_select_db("test", $con);

  $result = mysql_query("SELECT * FROM user");

  echo "<table border='1'>
  <tr>
  <th>Username</th>
  <th>Password</th>
  </tr>";

  while($row = mysql_fetch_array($result)) {
    echo "<tr>";
    echo "<td>" . $row['username'] . "</td>";
    echo "<td>" . $row['password'] . "</td>";
    echo "</tr>";
  }
  echo "</table>";

  mysql_close($con);

?>

<?php
  $con = mysql_connect("localhost","root","");
  if (!$con) {
    die('Could not connect: ' . mysql_error());
  }

  mysql_select_db("test", $con);

  mysql_query("DELETE FROM user WHERE username = '$_POST[username]'");

  mysql_close($con);
?>

<?php
  $con = mysql_connect("localhost:3306","root","");

  if (!$con) {
    die('Could not connect: ' . mysql_error());
  }

  mysql_select_db("test", $con);

  $sql = "INSERT INTO user (username,password)
  VALUES
  ('$_POST[username]','$_POST[password]')";

  if (!mysql_query($sql,$con)) {
    die('Error: ' . mysql_error());
  }

  echo "1 record added";

  mysql_close($con);

?>

<?php

  $con = mysql_connect("localhost","root","");
  if (!$con) {
    die('Could not connect: ' . mysql_error());
  }

  mysql_select_db("test", $con);

  mysql_query("UPDATE user SET password = '$_POST[password]' WHERE username = '$_POST[username]'");

  mysql_close($con);
?>

<html>
  <head>
    <title>用PHP向数据库中实现简单的增删改查</title>
  </head>
  <body>
    <br />
    <h1>Insert:</h1>
    <form action="insert.php" method="post">
      username:<input type="name" name="username"/>
      <br />
      password:<input type="password" name="password"/>
      <input type="submit" value="submit"/>
    </form>
    <br /><hr /><br />
    <h1>Delete</h1>
    <form action="delete.php" method="post">
      username:<input type="name" name="username" />
      <br />
      Are you sure?<input type="submit" value="sure" />
    </form>
    <br /><hr /><br />
    <h1>Update</h1>
    <form action="update.php" method="post">
      username:<input type="name" name="username"/>
      <br />
      You want to change your password into:<input type="password" name="password"/>
      <input type="submit" value="submit"/>
    </form>
    <br /><hr /><br />
  </body>
</html>