How to develop Projects(OLP) Using PHP and Mysql
Part 9
9️⃣ Online Learning Platform
Module 1: Add Course Details
📌 Folder Structure:
│── /courses/
│ ├── add_course.php # Add a new course
│ ├── edit_course.php # Edit an existing course
│ ├── delete_course.php # Delete a course
│ ├── course_list.php # List all courses
│ ├── course_detail.php # View single course details
Database Table:
CREATE TABLE courses (
id INT AUTO_INCREMENT PRIMARY KEY,
teacher_id INT NOT NULL,
title VARCHAR(255) NOT NULL,
description TEXT,
price DECIMAL(10,2) DEFAULT 0.00,
thumbnail VARCHAR(255),
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
FOREIGN KEY (teacher_id) REFERENCES users(id) ON DELETE CASCADE
);
📌 File: courses/add_course.php
// Include database connection
include('../config/db.php');
// Handling form submission
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
$teacher_id
= $_POST['teacher_id'];
$title = $_POST['title'];
$description
= $_POST['description'];
$price = $_POST['price'];
$thumbnail =
$_POST['thumbnail'];
// Input
validation
if (empty($teacher_id)
|| empty($title) || empty($price)) {
echo "Teacher
ID, title, and price are required!";
} else {
//
Insert query
$query =
"INSERT INTO courses (teacher_id, title, description, price, thumbnail)
VALUES ('$teacher_id', '$title', '$description', '$price', '$thumbnail')";
if ($conn->query($query)
=== TRUE) {
echo
"New course added successfully.";
} else {
echo
"Error: " . $query . "<br>" . $conn->error;
}
}
}
// Close connection
$conn->close();
?>
<!-- Basic HTML Form for adding a course -->
<!DOCTYPE html>
<html lang="en">
<head>
<meta
charset="UTF-8">
<meta
name="viewport" content="width=device-width,
initial-scale=1.0">
<title>Add Course</title>
</head>
<body>
<h2>Add a New Course</h2>
<form
action="add_course.php" method="POST">
<label for="teacher_id">Teacher ID:</label>
<input type="number" name="teacher_id"
required><br><br>
<label for="title">Course Title:</label>
<input type="text" name="title"
required><br><br>
<label for="description">Description:</label>
<textarea name="description"></textarea><br><br>
<label for="price">Price:</label>
<input type="number" step="0.01" name="price"
required><br><br>
<label for="thumbnail">Thumbnail URL:</label>
<input
type="text" name="thumbnail"><br><br>
<input type="submit" value="Add Course">
</form>
</body>
</html>
Explanation:
1.
Database Connection
- Uses MySQLi to connect to the database.
2.
Form Handling
- Checks if the request method is POST, retrieves input values, and validates
required fields.
3.
SQL Query Execution
- Uses a raw SQL query (INSERT INTO courses) without prepared statements.
4.
HTML Form
- A basic form to submit course details.
📌 File: courses/edit_course.php
<?php
// Include database connection
include('../config/db.php');
// Get course details if 'id' is provided
if (isset($_GET['id'])) {
$course_id =
$_GET['id'];
$query = "SELECT
* FROM courses WHERE id = '$course_id'";
$result = $conn->query($query);
if ($result->num_rows
> 0) {
$course
= $result->fetch_assoc();
} else {
die("Course
not found!");
}
}
// Handling form submission
if ($_SERVER["REQUEST_METHOD"] == "POST")
{
$course_id =
$_POST['course_id'];
$title = $_POST['title'];
$description
= $_POST['description'];
$price = $_POST['price'];
$thumbnail =
$_POST['thumbnail'];
// Input
validation
if (empty($title)
|| empty($price)) {
echo "Title
and price are required!";
} else {
//
Update query
$query =
"UPDATE courses SET
title = '$title',
description = '$description',
price = '$price',
thumbnail = '$thumbnail'
WHERE id = '$course_id'";
if ($conn->query($query)
=== TRUE) {
echo
"Course updated successfully.";
} else {
echo
"Error: " . $query . "<br>" . $conn->error;
}
}
}
// Close connection
$conn->close();
?>
<!-- Basic HTML Form for editing a course -->
<!DOCTYPE html>
<html lang="en">
<head>
<meta
charset="UTF-8">
<meta
name="viewport" content="width=device-width,
initial-scale=1.0">
<title>Edit Course</title>
</head>
<body>
<h2>Edit Course</h2>
<form
action="edit_course.php" method="POST">
<input type="hidden" name="course_id" value="<?php
echo isset($course['id']) ? $course['id'] : ''; ?>">
<label for="title">Course Title:</label>
<input type="text" name="title" value="<?php
echo isset($course['title']) ? $course['title'] : ''; ?>"
required><br><br>
<label for="description">Description:</label>
<textarea name="description"><?php echo isset($course['description'])
? $course['description'] : ''; ?></textarea><br><br>
<label for="price">Price:</label>
<input
type="number" step="0.01" name="price" value="<?php
echo isset($course['price']) ? $course['price'] : ''; ?>"
required><br><br>
<label for="thumbnail">Thumbnail URL:</label>
<input type="text" name="thumbnail" value="<?php
echo isset($course['thumbnail']) ? $course['thumbnail'] : '';
?>"><br><br>
<input type="submit" value="Update Course">
</form>
</body>
</html>
Explanation:
1.
Database Connection
- Connects using MySQLi.
2.
Fetching Course Data -
Retrieves course details from the database using $_GET['id'].
3.
Form Submission
- Updates course details in the database using UPDATE query.
4.
HTML Form
- Displays the existing data in input fields for editing.
📌 File: courses/delete_course.php
<?php
// Include database connection
include('../config/db.php');
// Check if course ID is provided
if (isset($_GET['id'])) {
$course_id =
$_GET['id'];
// Delete
query
$query = "DELETE
FROM courses WHERE id = '$course_id'";
if ($conn->query($query)
=== TRUE) {
echo "Course
deleted successfully.";
} else {
echo "Error:
" . $query . "<br>" . $conn->error;
}
} else {
echo "Invalid
request. Course ID is required.";
}
// Close connection
$conn->close();
?>
Explanation:
1.
Database Connection
- Connects using MySQLi.
2.
Check for Course ID
- Retrieves id from the $_GET request.
3.
Delete Query Execution
- Runs DELETE FROM courses WHERE id = '$course_id'.
4.
Success/Error Handling
- Displays success or error messages.
courses/course_detail.php
<?php
// Include database connection
include('../config/db.php');
// Check if course ID is provided
if (isset($_GET['id'])) {
$course_id =
$_GET['id'];
// Fetch
course details
$query = "SELECT
* FROM courses WHERE id = '$course_id'";
$result = $conn->query($query);
if ($result->num_rows
> 0) {
$course
= $result->fetch_assoc();
} else {
die("Course
not found!");
}
} else {
die("Invalid
request. Course ID is required.");
}
// Close connection
$conn->close();
?>
<!-- Basic HTML to display course details -->
<!DOCTYPE html>
<html lang="en">
<head>
<meta
charset="UTF-8">
<meta
name="viewport" content="width=device-width,
initial-scale=1.0">
<title>Course Details</title>
</head>
<body>
<h2>Course Details</h2>
<p><strong>Title:</strong> <?php echo isset($course['title'])
? $course['title'] : ''; ?></p>
<p><strong>Description:</strong> <?php echo isset($course['description'])
? $course['description'] : 'No description available.'; ?></p>
<p><strong>Price:</strong> $<?php echo isset($course['price'])
? $course['price'] : '0.00'; ?></p>
<p><strong>Created At:</strong> <?php echo isset($course['created_at'])
? $course['created_at'] : ''; ?></p>
<?php if
(!empty($course['thumbnail'])): ?>
<p><strong>Thumbnail:</strong></p>
<img
src="<?php echo $course['thumbnail']; ?>" alt="Course
Thumbnail" width="200">
<?php endif;
?>
<br>
<a href="courses.php">Back
to Courses</a>
</body>
</html>
Explanation:
1.
Database Connection
- Uses MySQLi.
2.
Retrieve Course Data
- Gets course details using SELECT * FROM courses WHERE id = '$course_id'.
3.
Check for Valid Course ID
- If no valid id is provided, it exits.
4.
Display Course Details
- Outputs title, description, price, created date, and thumbnail (if
available).
5. Back to Courses Link - Provides navigation.
📌 File: courses/course_list.php
<?php
// Include database connection
include('../config/db.php');
// Fetch all courses
$query = "SELECT * FROM courses ORDER BY
created_at DESC";
$result = $conn->query($query);
?>
<!-- Basic HTML to display course list -->
<!DOCTYPE html>
<html lang="en">
<head>
<meta
charset="UTF-8">
<meta
name="viewport" content="width=device-width,
initial-scale=1.0">
<title>Course List</title>
</head>
<body>
<h2>Course List</h2>
<?php if
($result->num_rows > 0): ?>
<table border="1" cellpadding="10">
<tr>
<th>ID</th>
<th>Title</th>
<th>Price</th>
<th>Created At</th>
<th>Actions</th>
</tr>
<?php
while ($course = $result->fetch_assoc()): ?>
<tr>
<td><?php echo $course['id']; ?></td>
<td><?php echo $course['title']; ?></td>
<td>$<?php echo $course['price']; ?></td>
<td><?php echo $course['created_at']; ?></td>
<td>
<a href="course_detail.php?id=<?php echo $course['id'];
?>">View</a> |
<a href="edit_course.php?id=<?php echo $course['id'];
?>">Edit</a> |
<a href="delete_course.php?id=<?php echo $course['id'];
?>" onclick="return confirm('Are you sure?');">Delete</a>
</td>
</tr>
<?php
endwhile; ?>
</table>
<?php else:
?>
<p>No courses available.</p>
<?php endif;
?>
<br>
<a href="add_course.php">Add
New Course</a>
</body>
</html>
<?php
// Close connection
$conn->close();
?>
Explanation:
1.
Database Connection -
Uses MySQLi to connect to the database.
2.
Retrieve All Courses
- Fetches all courses sorted by created_at DESC.
3.
Display Course List
- Uses an HTML table to display the course details.
4.
Action Links
- Provides options to View, Edit, and Delete each course.
5.
Add New Course Button
- Provides a link to add a new course.