Master PHP Programming: Comprehensive Guide to Web Development, Form Handling, and Database Integration

 

PHP Tutorial for Zed ICT Hub

Table of Contents

1. Introduction to PHP

   • What is PHP?
   • Features of PHP
   • Setting Up the Environment

2. Basic PHP Syntax

   • PHP Tags and Comments
   • Variables and Data Types
   • Operators

3. Control Structures

   • Conditional Statements (if, else, switch)
   • Looping Statements (for, while, foreach)

4. Functions in PHP

   • Defining Functions
   • Function Arguments and Return Values
   • Built-in Functions

5. Working with Arrays

   • Indexed Arrays
   • Associative Arrays
   • Multi-dimensional Arrays
   • Array Functions

6. Form Handling

   • Getting Data from Forms
   • Validating Form Data
   • Processing Form Data

7. Working with Files

   • Reading and Writing Files
   • File Uploads

8. PHP and Databases

   • Introduction to MySQL
   • Connecting to a Database
   • Performing CRUD Operations

9. Object-Oriented Programming (OOP) in PHP

   • Classes and Objects
   • Inheritance
   • Encapsulation and Polymorphism

10. Final Project: Simple Blog Application

    • Project Overview
    • Step-by-Step Implementation
    • Final Code and Explanation

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1. Introduction to PHP

What is PHP? PHP (Hypertext Preprocessor) is a popular server-side scripting language designed for web development but also used as a general-purpose programming language. It is especially suited for creating dynamic web pages and can be embedded into HTML.

Features of PHP:

• Open-source and free to use
• Cross-platform compatibility
• Supports various databases
• Extensive community and library support

Setting Up the Environment: To run PHP, you need a web server (like Apache) and PHP installed. You can use tools like XAMPP or MAMP to set up a local server easily.

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2. Basic PHP Syntax

PHP Tags and Comments: PHP code is written between <?php and ?> tags.

php
<?php
// This is a single-line comment
# This is also a single-line comment
/*
This is a multi-line comment
*/
?>

Variables and Data Types: Variables in PHP start with the $ sign. PHP supports several data types: strings, integers, floats, booleans, arrays, and objects.

php
$name = "John Doe"; // String
$age = 30; // Integer
$salary = 2500.50; // Float
$isEmployed = true; // Boolean

Operators: PHP supports various operators, including arithmetic, assignment, comparison, and logical operators.

php
$sum = $a + $b; // Arithmetic

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3. Control Structures

Conditional Statements: PHP supports conditional statements to execute different actions based on different conditions.

php
if ($age >= 18) {
    echo "You are an adult.";
} else {
    echo "You are a minor.";
}

Looping Statements: Loops allow you to execute a block of code multiple times.

php
// For Loop
for ($i = 0; $i < 5; $i++) {
    echo $i;
}
// While Loop
$i = 0;
while ($i < 5) {
    echo $i;
    $i++;
}

---

4. Functions in PHP

Defining Functions: Functions are reusable blocks of code.

php
function greet($name) {
    return "Hello, " . $name;
}
echo greet("John"); // Output: Hello, John

Function Arguments and Return Values: You can pass parameters to functions and return values from them.

php
function add($a, $b) {
    return $a + $b;
}
echo add(5, 10); // Output: 15

Built-in Functions: PHP provides many built-in functions like strlen(), str_replace(), array_push(), etc.

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5. Working with Arrays

Indexed Arrays: Arrays that use numeric indexes.

php
$fruits = array("Apple", "Banana", "Cherry");
echo $fruits[1]; // Output: Banana

Associative Arrays: Arrays that use named keys.

php
$person = array("name" => "John", "age" => 30);
echo $person["name"]; // Output: John

Multi-dimensional Arrays: Arrays that contain other arrays.

php
$cars = array(
    array("Volvo", 22, 18),
    array("BMW", 15, 13),
);
echo $cars[1][0]; // Output: BMW

Array Functions: PHP provides numerous functions to manipulate arrays, such as count(), sort(), and array_merge().

---

6. Form Handling

Getting Data from Forms: You can collect data using $_GET and $_POST superglobals.

php
// HTML Form
<form method="post" action="process.php">
    <input type="text" name="username">
    <input type="submit" value="Submit">
</form>
// PHP Script
$username = $_POST['username'];

Validating Form Data: Always validate and sanitize input to prevent security vulnerabilities.

php
$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);

---

7. Working with Files

Reading and Writing Files: PHP provides functions to read from and write to files.

php
// Writing to a file
file_put_contents("example.txt", "Hello World!");
// Reading from a file
$content = file_get_contents("example.txt");
echo $content; // Output: Hello World!

File Uploads: You can handle file uploads using forms and $_FILES superglobal.

html
<form method="post" enctype="multipart/form-data">
    <input type="file" name="fileToUpload">
    <input type="submit" value="Upload">
</form>

---

8. PHP and Databases

Introduction to MySQL: MySQL is a popular relational database management system. You can connect to it using PHP.

Connecting to a Database:

php
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

Performing CRUD Operations:

• Create: Inserting data into the database.
• Read: Retrieving data from the database.
• Update: Modifying existing data.
• Delete: Removing data.

Example of inserting data:

php
$sql = "INSERT INTO users (name, age) VALUES ('John', 30)";
$conn->query($sql);

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9. Object-Oriented Programming (OOP) in PHP

Classes and Objects: PHP supports OOP principles, allowing you to create classes and objects.

php
class Car {
    public $color;
    public function __construct($color) {
        $this->color = $color;
    }
}
$myCar = new Car("red");
echo $myCar->color; // Output: red

Inheritance: Classes can inherit properties and methods from other classes.

php
class Vehicle {
    public $type;
}
class Car extends Vehicle {
    public function __construct($type) {
        $this->type = $type;
    }
}

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10. Final Project: Simple Blog Application

Project Overview:

We will create a simple blog application that allows users to create, view, edit, and delete posts.

Step-by-Step Implementation:

1. Database Setup:

   • Create a database named blog.
   • Create a table posts with columns id, title, content, and created_at.

2. HTML Form for Creating a Post:

   html
   <form method="post" action="create_post.php">
       <input type="text" name="title" placeholder="Post Title">
       <textarea name="content" placeholder="Post Content"></textarea>
       <input type="submit" value="Create Post">
   </form>

3. PHP Code for Creating a Post (create_post.php):

   php
   if ($_SERVER['REQUEST_METHOD'] == 'POST') {
       $title = $_POST['title'];
       $content = $_POST['content'];
       $sql = "INSERT INTO posts (title, content, created_at) VALUES ('$title', '$content', NOW())";
       $conn->query($sql);
       header("Location: view_posts.php");
   }

4. Display Posts (view_posts.php):

   php
   $result = $conn->query("SELECT * FROM posts");
   while ($row = $result->fetch_assoc()) {
       echo "<h2>" . $row['title'] . "</h2>";
       echo "<p>" . $row['content'] . "</p>";
   }

5. Final Code and Explanation:

   • Combine the above files and ensure the database connection is established.
   • Test the blog application