I'm still learning PHP OOP. So I'd like to seek for some expert advice or criticism regarding this code I created.

In this script, I created the objects I need to process the user input from a form. While the $homepage object is responsible for displaying the whole webpage.

My questions are:

Is this consider clean code? Can I completely hide the fact that I actually include the autoload and the configuration files? Any recommendation or tips to improve my code?

<?php

/**
*
* OOP practice
* @author Joey
*/

require_once 'config/autoload.php';
require_once 'config/config.php';

// Database credentials

$host = $config['host'];
$dbname = $config['dbname'];
$username = $config['username'];
$password = $config['password'];

// Short variable names

$fname = isset($_POST['fname']) ? clean_data($_POST['fname']) : null;
$lname = isset($_POST['lname']) ? clean_data($_POST['lname']) : null;
$your_question = isset($_POST['question']) ? clean_data($_POST['question']) : null;

try {

    // Page object

    $homepage = new Page('Questions and Answers', 'QA', '', 'You ask, we answer');

    // Author object

    $author = new Author($fname, $lname);

    // Question object

    $question = new Question($your_question, $author);

    // Database object

    $pdo = new DbConnect($host, $dbname, $username, $password);

    // Connect to the database

    $pdo->open_connection();
} catch (Exception $e) {
    echo $e->getMessage(), '<br>';
    exit;
} catch (PDOException $e) {
    echo $e->GetMessage(), '<br>';
    exit;
}

if (isset($_POST['submit'])) {
    // Insert the user input into the database

    $pdo->execute_query('INSERT INTO author (first_name, last_name) VALUES (?, ?)', array($author->getFirstName(), $author->GetLastName()));
    $pdo->close_connection();
    $homepage->content = '<h3>Your question</h3><br><p>Hello ' . $author->getFirstName() . ' ' . $author->getLastName() . '!' . '</p><br>';
    $homepage->content .= '<p>You ask: ' . $question->getQuestion() . '</p><br>';
    $homepage->content .= 'Do you want to ';
    $homepage->content .= '<a href="index.php">Ask another question?</a>' . ' ' . '<br>';
} else {
    // Display the form

    $homepage->content = <<<_END

    <h3>Your question here</h3><br>
    <form action="{$_SERVER['PHP_SELF']}" method="post" role="form">
        <label for="fname">Enter your first name</label><br>
     <input type="text" id="fname" name="fname" size="30"><br>
        <label for="lname">Enter your last name</label><br>
        <input type="text" id="lname" name="lname" size="30"><br>
        <label for="question">What is your question?</label><br>
        <textarea id="question" name="question" rows="10" cols="70"></textarea><br>
        <input type="submit" name="submit" value="Submit">
    </form>

_END; }

// Display the webpage using the Page class

$homepage->display();

function clean_data($data)
{
    $data = trim($data);
    $data = strip_tags($data);
    $data = addslashes($data);
    return $data;
}

I'm still learning PHP OOP, so I'd like to seek for some expert advice or criticism regarding this code I created.

In this script, I created the objects I need to process the user input from a form. While the $homepage object is responsible for displaying the whole webpage.

My questions are:

1. Is this consider clean code?
2. Can I completely hide the fact that I actually include the autoload and the configuration files?
3. Any recommendation or tips to improve my code?

<?php

/**
*
* OOP practice
* @author Joey
*/

require_once 'config/autoload.php';
require_once 'config/config.php';

// Database credentials

$host = $config['host'];
$dbname = $config['dbname'];
$username = $config['username'];
$password = $config['password'];

// Short variable names

$fname = isset($_POST['fname']) ? clean_data($_POST['fname']) : null;
$lname = isset($_POST['lname']) ? clean_data($_POST['lname']) : null;
$your_question = isset($_POST['question']) ? clean_data($_POST['question']) : null;

try {

    // Page object

    $homepage = new Page('Questions and Answers', 'QA', '', 'You ask, we answer');

    // Author object

    $author = new Author($fname, $lname);

    // Question object

    $question = new Question($your_question, $author);

    // Database object

    $pdo = new DbConnect($host, $dbname, $username, $password);

    // Connect to the database

    $pdo->open_connection();
} catch (Exception $e) {
    echo $e->getMessage(), '<br>';
    exit;
} catch (PDOException $e) {
    echo $e->GetMessage(), '<br>';
    exit;
}

if (isset($_POST['submit'])) {
    // Insert the user input into the database

    $pdo->execute_query('INSERT INTO author (first_name, last_name) VALUES (?, ?)', array($author->getFirstName(), $author->GetLastName()));
    $pdo->close_connection();
    $homepage->content = '<h3>Your question</h3><br><p>Hello ' . $author->getFirstName() . ' ' . $author->getLastName() . '!' . '</p><br>';
    $homepage->content .= '<p>You ask: ' . $question->getQuestion() . '</p><br>';
    $homepage->content .= 'Do you want to ';
    $homepage->content .= '<a href="index.php">Ask another question?</a>' . ' ' . '<br>';
} else {
    // Display the form

    $homepage->content = <<<_END

    <h3>Your question here</h3><br>
    <form action="{$_SERVER['PHP_SELF']}" method="post" role="form">
        <label for="fname">Enter your first name</label><br>
     <input type="text" id="fname" name="fname" size="30"><br>
        <label for="lname">Enter your last name</label><br>
        <input type="text" id="lname" name="lname" size="30"><br>
        <label for="question">What is your question?</label><br>
        <textarea id="question" name="question" rows="10" cols="70"></textarea><br>
        <input type="submit" name="submit" value="Submit">
    </form>
_END;
}

// Display the webpage using the Page class

$homepage->display();

function clean_data($data)
{
    $data = trim($data);
    $data = strip_tags($data);
    $data = addslashes($data);
    return $data;
}