Web Designing

Group A: Multiple Choice Questions (2 × 10 = 20 Marks)

To secure full marks in Group A, candidates must state the correct option and provide a concise, theoretically sound justification citing standard PHP/MySQL mechanics.

2. PHP Basics, Dynamic Web Apps, & Operator Evaluation (3+3+2 Marks)

a) Definition of PHP & Its Role in Dynamic Applications

Role in Developing Dynamic Internet Applications:

• Server-Side Processing: PHP code executes entirely on the server. The client browser only receives the compiled, pure HTML output, keeping the proprietary business logic hidden and secure.
• Database Integration: It acts as a middleware bridge, communicating with relational databases (like MySQL) to fetch, manipulate, and update structured records dynamically in real time.
• Dynamic Page Composition: Instead of loading static files, PHP compiles pages on the fly based on user input, session states, and custom database records. This is essential for features like authentication, search filters, and dashboard displays.

b) Static vs. Dynamic Websites

Key Advantages of Dynamic Websites:

1. Highly Interactive & Personalized: Delivers unique experiences, such as user dashboards, personalized shopping recommendations, and localized content based on user profiles.
2. Centralized Data Management: Content updates can be easily made via a Content Management System (CMS) or database, eliminating the need to edit static HTML code across thousands of files.
3. Scalability: Managing massive systems (such as e-commerce catalogs or news hubs) is efficient, as a single dynamic template file can render millions of unique product pages on demand.

c) Evaluation of Key Operators in PHP

Operators are syntax symbols that perform operations on one or more values (operands). PHP supports several major operator classes:

3. Variables, Constants, Scopes, & Control Flows (2+3+3 Marks)

a) Variables and Constants in PHP

b) Variable Scopes in PHP

The scope of a variable defines where it can be accessed or modified within a script. PHP enforces three distinct scopes:

1. Local Scope: A variable declared inside a function has local scope and can only be accessed within that function.
   function calc() { $x = 10; echo $x; } // $x is inaccessible outside calc()
2. Global Scope: A variable declared outside functions has global scope. To access a global variable inside a function, use the global keyword or reference the superglobal $GLOBALS array.
   $g = 50;
function access() { global $g; echo $g; /* Or: echo $GLOBALS['g']; */ }
3. Static Scope: Typically, local variables are destroyed when a function finishes executing. Declaring a variable as static preserves its value across sequential function calls, allowing it to act as a local accumulator.
   function tracker() { static $hits = 0; $hits++; echo $hits; }

c) Structural Difference: FOR vs. FOREACH Loops

<?php
// Standard FOR Loop execution
for ($i = 0; $i < 3; $i++) {
    echo "Counter: $i | ";
}

echo "\n";

// Dynamic FOREACH Loop traversing an Associative Array
$memberRoles = ["Admin" => "John", "Editor" => "Sara"];
foreach ($memberRoles as $role => $name) {
    echo "$name is the $role | ";
}
?>

4. Array Implementations & Custom Sorting Mechanics (1+4+3 Marks)

a) What is an Array in PHP?

b) Indexed vs. Associative Arrays

c) Sorting Functions and Custom Implementations

PHP provides highly optimized, built-in sorting functions. Key functions include:

• sort(): Sorts an indexed array's values in ascending order.
• asort(): Sorts an associative array's values in ascending order while maintaining key-value associations.
• ksort(): Sorts an associative array by its keys in ascending order.

<?php
$students = ["Mark" => 88, "Alice" => 95, "Zack" => 79];

// Sort by value, preserving key associations (ascending)
asort($students);
print_r($students);
/* Output:
Array (
    [Zack] => 79
    [Mark] => 88
    [Alice] => 95
) */

// Sort alphabetically by key (ascending)
ksort($students);
print_r($students);
/* Output:
Array (
    [Alice] => 95
    [Mark] => 88
    [Zack] => 79
) */
?>

5. Functions, Arguments, Call-by-Value & Call-by-Reference (3+3+2 Marks)

a) Function Parameter Passing Mechanics

PHP supports passing parameters to functions both by value (default) and by reference.

function addFive($num) {
    $num += 5;
}
$val = 10;
addFive($val);
// $val is still 10

function addFiveRef(&$num) {
    $num += 5;
}
$val = 10;
addFiveRef($val);
// $val is now 15

b) Default Arguments in PHP Functions

Default arguments allow you to define default values for parameters. If the caller does not pass a value for that parameter, the function will use the pre-assigned default value instead.

<?php
// Default values are defined directly in the function signature
function generateTaxInvoice($baseAmount, $taxRate = 18) {
    $tax = ($baseAmount * $taxRate) / 100;
    return $baseAmount + $tax;
}

// Case 1: Caller overrides the default tax rate parameter
echo "Custom Rate (5%): " . generateTaxInvoice(1000, 5) . "\n"; // Yields 1050

// Case 2: Caller omits the second parameter, falling back to 18%
echo "Default Rate (18%): " . generateTaxInvoice(1000) . "\n"; // Yields 1180
?>

6. MySQL Data Manipulation & PHP Connection APIs (2+2+4 Marks)

a) Data Manipulation in MySQL

Data Manipulation Language (DML) statements are used to manage data within existing database schemas. Key DML statements include:

b) PHP Database Connection APIs: MySQLi vs. PDO

PHP provides two main object-oriented extensions for connecting to and interacting with MySQL databases:

7. String Operations, State persistence (Cookies & Sessions) (2+4+2 Marks)

a) Standard String Functions in PHP

PHP has built-in functions designed for string manipulation, which are essential for validation and parsing:

• strpos(string $haystack, string $needle): int|false: Finds the position of the first occurrence of a substring. Returns false if the substring is not found.
• str_replace(mixed $search, mixed $replace, mixed $subject): mixed: Replaces all occurrences of a search string with a replacement string within a target string.
• trim(string $string): string: Strips whitespace (or other specified characters) from the beginning and end of a string.

b) Cookies in PHP: Setting, Viewing, and Deleting

<?php
// 1. Setting a Cookie (Expires in 1 hour, accessible across the site)
$cookieValue = "Jane Doe";
setcookie("user_profile", $cookieValue, time() + 3600, "/");

// 2. Viewing/Accessing a Cookie (Using the $_COOKIE superglobal)
if (isset($_COOKIE["user_profile"])) {
    echo "Welcome back, " . htmlspecialchars($_COOKIE["user_profile"]) . "!";
} else {
    echo "No profile cookie found.";
}

// 3. Deleting a Cookie (Set the expiration time to the past)
setcookie("user_profile", "", time() - 3600, "/");
?>

c) Unsetting Session Variables in PHP

To clear a specific variable from an active session, use the unset() function on the target key within the $_SESSION superglobal array.

<?php
session_start();

// Unset a specific session variable
unset($_SESSION['cart_items']);

// To unset all session variables at once (safer than reassigning $_SESSION)
session_unset();
?>

8. Web Framework Architecture, MVC & Global Framework Comparison (2+4+2 Marks)

a) What is a PHP Framework?

b) The MVC (Model-View-Controller) Architectural Pattern

MVC is a software design pattern that separates an application into three interconnected components, dividing business logic from the user interface.

Significance of MVC in Web Development:

• Separation of Concerns: Isolates user interface code from business logic, making it easier to manage and scale large applications.
• Parallel Development Workflow: Front-end designers can work on the HTML templates (Views) at the same time backend engineers build the core database queries (Models) and routing logic (Controllers).
• Improved Maintainability: Changes to the database schema or styling templates are isolated, reducing the risk of introducing bugs across the application.

c) Popular PHP Frameworks & Key Features

9. Dynamic Database Insertion & Secure Form Integration (3+5 Marks)

a) The Process of Data Insertion from PHP to MySQL

To safely insert dynamic web data into a relational database, you must follow these steps:

1. Initialize Connection: Create a persistent database connection (such as PDO or MySQLi) from PHP to the target database server.
2. Retrieve & Sanitize Input: Fetch data from the HTTP request (e.g., using the $_POST superglobal) and validate or sanitize it to ensure it matches the expected format.
3. Prepare SQL Statement: Compile an INSERT INTO statement with parameter placeholders (rather than direct string concatenation) to prevent SQL injection.
4. Bind Parameters & Execute: Bind the sanitized inputs to the pre-compiled parameters and execute the query on the database server.
5. Verify Status: Confirm if the database write was successful and display a clean status message to the user.

b) Secure Form Data Insertion Code (Object-Oriented MySQLi with Prepared Statements)

This script securely processes incoming form data submitted via the POST method and writes it to a MySQL database using the MySQLi extension.

<?php
// Database credentials
$host     = "localhost";
$dbUser   = "admin_root";
$dbPass   = "app_pass_321";
$dbSchema = "catalog_db";

// 1. Establish an object-oriented connection to MySQLi
$mysqli = new mysqli($host, $dbUser, $dbPass, $dbSchema);

// Verify connection integrity
if ($mysqli->connect_error) {
    die("Database Connection Error: " . $mysqli->connect_error);
}

// 2. Intercept and process POST data
if ($_SERVER["REQUEST_METHOD"] === "POST") {
    // Retrieve and sanitize inputs
    $itemTitle = trim($_POST['itemTitle'] ?? '');
    $itemPrice = floatval($_POST['itemPrice'] ?? 0.0);

    // Validate inputs
    if (!empty($itemTitle) && $itemPrice > 0) {
        // 3. Prepare the SQL insert statement using parameter placeholders
        $sql = "INSERT INTO products (title, price) VALUES (?, ?)";
        $stmt = $mysqli->prepare($sql);

        if ($stmt) {
            // 4. Bind variables to the prepared statement as parameters
            // "sd" denotes types: s = string, d = double (float)
            $stmt->bind_param("sd", $itemTitle, $itemPrice);

            // 5. Execute query and verify status
            if ($stmt->execute()) {
                echo "<div class='key-point'><span class='klabel'>Success</span>Product successfully written to inventory.</div>";
            } else {
                echo "<div class='warning'><span class='wlabel'>Database Error</span>" . $stmt->error . "</div>";
            }
            // Close statement
            $stmt->close();
        } else {
            echo "Failed to compile SQL statement.";
        }
    } else {
        echo "<div class='warning'><span class='wlabel'>Validation Failure</span>Please provide a valid product title and positive price.</div>";
    }
}

// Close connection
$mysqli->close();
?>

10. CodeIgniter Helpers: Design, Types, & Loading Mechanisms (4+4 Marks)

a) Commonly Used CodeIgniter Helpers and Their Purposes

b) Loading Helpers in CodeIgniter

Helpers must be explicitly loaded before their functions can be called. This can be done dynamically inside a controller method or globally via the autoload configuration.

// CodeIgniter 3/4 Controller Implementation
class AccountController extends CI_Controller {

    public function register() {
        // Dynamic loading of URL and Form helpers
        $this->load->helper(['url', 'form']);

        // Use helper functions directly
        $formDestination = site_url('account/save');

        // Load target registration view
        $this->load->view('register_form', ['target' => $formDestination]);
    }
}

// In CodeIgniter 4, you can also use helper() directly:
// helper(['url', 'form']);

Web Designing Past Paper Solutions · Hand-crafted Exam Notes · Aligned with June 2024 Syllabus Guidelines.