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A Simple Database Application

In this exercise you will create a simple guestbook database and HTML pages that allow a user to leave a message or view other users' messages.

  1. Connect to the MySQL server by opening a command window and navigating to the directory where MySQL stores its executable files (on my computer, this would be X:\xampp\mysql\bin) and enter the command:

    mysql -u root


  2. Enter the command:

    create database guestbook;


  3. Enter the command:

    use guestbook;


  4. Create the "message" table using the following command:

    create table message
    (
     guestName varchar(30),
     msg text
    );


  5. Exit the MySQL command shell by typing:

    quit


  6. In the root of your MoWeS server (on my computer, this would be X:\xampp\htdocs), create a file called "guestbook.html", and in it enter the following code:

    <html>
      <head>
        <title>
          Guestbook
        </title>
      </head>

      <body>

        <h1>Guest Book</h1>

        <p>Please enter your name and message:</p>

        <form action="guestbook.php" method="post">
          <table>
            <tr>
              <td align="right">Name: </td>
              <td><input type="text" size="20" maxlength="30" name="name"></td>
            </tr>
            <tr>
              <td align="right" valign="top">Message: </td>
              <td><textarea rows="6" cols="40" name="message"></textarea></td>
            </tr>
            <tr>
              <td colspan="2" align="right"><input type="submit" value="Leave message"></td>
            </tr>
          </table>
        </form>

        <p><a href="display_messages.php">Display messages</a>.</p>

      </body>
    </html>

  7. Create a file called "guestbook.php", and in it enter the following code:

    <html>
      <head>
        <title>
          Guestbook
        </title>
      </head>

      <body>

        <h1>Guest Book</h1>

    <?php

    $name = $_POST['name'];
    $message = $_POST['message'];

    // connect to MySQL
    $conn = @mysql_connect ( "localhost", "root", "")
        or die (mysql_error());

    // select the database
    $rs = @mysql_select_db ( "guestbook", $conn ) or die (mysql_error());

    //Create the query
    $sql = "INSERT INTO message(guestName, msg) VALUES ('$name','$message')";

    // execute the query
    $rs = mysql_query( $sql, $conn ) or die (mysql_error());

    ?>

        <p>Message successfully saved.</p>
        <p>Click <a href="guestbook.html">here</a> to return to Guestbook.</p>

      </body>
    </html>


  8. Create a file called "display_messages.php", and in it enter the following code:

    <html>
      <head>
        <title>
          Guestbook
        </title>
      </head>

      <body>

        <h1>Guest Book</h1>

        <p>Click <a href="guestbook.html">here</a> to return to Guestbook.</p>

        <h3>Messages:</h3>

    <?php

    // connect to MySQL
    $conn = @mysql_connect ( "localhost", "root", "")
    or die ("Sorry - unable to connect to MySQL database " );

    // select the database
    $rs = @mysql_select_db ( "guestbook", $conn ) or die ( "error" );

    //Create the query
    $sql = "SELECT * FROM message";

    // execute the query
    $rs = mysql_query( $sql,$conn );

    // display the results
    echo ( "<table border='1'><tr><td><b>Name</b></td><td><b>Message</b></td></tr>" );

    while ( $row = mysql_fetch_array( $rs ) )
    {
        echo ( "<tr><td>".$row["guestName"]."</td><td>".$row["msg"]."</td></tr>" );
    }
    echo ( "</table>" );
    ?>

        </body>
    </html>

Once you have created these files, open the "guestbook.html" page and enter some messages. You should be able to view your messages by clicking on the "Display messages" link on the "guestbook.html" page.


The guestbook data entry form

The guestbook data entry form



The output from "guestbook.php"

The output from "guestbook.php"



The output from "display_messages.php"

The output from "display_messages.php"