index.php

 <!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
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    <title>PHP - MYSQL - CRUD</title>
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</head>

<body>
<section>
    <h1 style="text-align: center;margin: 50px 0;">PHP CRUD operations with MySQL</h1>
    <div class="container">
        <form action="adddata.php" method="post">
            <div class="row">
                <div class="form-group col-lg-4">
                    <label for="">Student Name</label>
                    <input type="text" name="name" id="name" class="form-control" required>
                </div>
                <div class="form-group  col-lg-3">
                    <label for="">Grade</label>
                    <select name="grade" id="grade" class="form-control" required>
                        <option value="">Select a Grade</option>
                        <option value="grade6">Grade 6</option>
                        <option value="grade7">Grade 7</option>
                        <option value="grade8">Grade 8</option>
                        <option value="grade9">Grade 9</option>
                        <option value="grade10">Grade 10</option>
                    </select>
                </div>
                <div class="form-group col-lg-3">
                    <label for="">Marks</label>
                    <input type="number" name="marks" id="marks" class="form-control" required>
                </div>
                <div class="form-group col-lg-2" style="display: grid;align-items:  flex-end;">
                    <input type="submit" name="submit" id="submit" class="btn btn-primary">
                </div>
            </div>
        </form>
    </div>
</section>

<section style="margin: 50px 0;">
    <div class="container">
        <table class="table table-dark">
            <thead>
            <tr>
                <th scope="col">Id</th>
                <th scope="col">Student Name</th>
                <th scope="col">Grade</th>
                <th scope="col">Marks</th>
                <th scope="col">Edit</th>
                <th scope="col">Delete</th>
            </tr>
            </thead>
            <tbody>
            <?php
            global $conn;
            require_once "conn.php";

            $sql_query = "SELECT * FROM results";

            try {
                // Prepare and execute the query
                $stmt = $conn->prepare($sql_query);
                $stmt->execute();

                // Fetch results as an associative array
                while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
                    $Id = $row['id'];
                    $Name = $row['name'];
                    $Grade = $row['class'];
                    $Marks = $row['marks'];
                    ?>

                    <tr class="trow">
                        <td><?php echo htmlspecialchars($Id); ?></td>
                        <td><?php echo htmlspecialchars($Name); ?></td>
                        <td><?php echo htmlspecialchars($Grade); ?></td>
                        <td><?php echo htmlspecialchars($Marks); ?></td>
                        <td><a href="updatedata.php?id=<?php echo htmlspecialchars($Id); ?>" class="btn btn-primary">Edit</a></td>
                        <td><a href="delete.php?id=<?php echo htmlspecialchars($Id); ?>" class="btn btn-danger">Delete</a></td>
                    </tr>

                    <?php
                }
            } catch (PDOException $e) {
                echo "Error: " . htmlspecialchars($e->getMessage());
            }
            ?>

            </tbody>
        </table>
    </div>
</section>
</body>

</html>