PDO Database Connection:

<?php
try {
    $pdo = new PDO("mysql:host=localhost;dbname=your_database_name", "your_username", "your_password");
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
} catch (PDOException $e) {
    die("Connection failed: " . $e->getMessage());
}
?>

CRUD Operations with PDO:

Create (INSERT):

try {
    $sql = "INSERT INTO your_table (column1, column2, column3) VALUES (:value1, :value2, :value3)";
    $stmt = $pdo->prepare($sql);
    $stmt->bindParam(':value1', $value1);
    $stmt->bindParam(':value2', $value2);
    $stmt->bindParam(':value3', $value3);

    $value1 = "Some Value";
    $value2 = "Another Value";
    $value3 = 123;

    $stmt->execute();
    echo "Record inserted successfully.";
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

Read (SELECT) WIthout Loop:

 try {
        $sql = "SELECT * FROM users WHERE user_email = :email AND user_password = :password";
        $stmt = $pdo->prepare($sql);
$stmt->bindParam(':email', $l_email);
        $stmt->bindParam(':password', $encrypted_password);
        $stmt->execute();

        $row = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($row) {
            $user_id = $row['id'];

            if ($user_id != '') {
                $message = 'Logged in Successfully';
            } else {
                $message = 'Invalid email or password';
            }
        } else {
            $message = 'Invalid email or password';
        }
        
        echo $message;
    } catch (PDOException $e) {
        echo "Error: " . $e->getMessage();
    }

Update (UPDATE):

try {
    $sql = "UPDATE your_table SET column1 = :value1, column2 = :value2 WHERE id = :id";
    $stmt = $pdo->prepare($sql);
    $stmt->bindParam(':value1', $value1);
    $stmt->bindParam(':value2', $value2);
    $stmt->bindParam(':id', $id);

    $value1 = "Updated Value";
    $value2 = "New Value";
    $id = 1; // Example record ID

    $stmt->execute();
    echo "Record updated successfully.";
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

Delete (DELETE):

try {
    $sql = "DELETE FROM your_table WHERE id = :id";
    $stmt = $pdo->prepare($sql);
    $stmt->bindParam(':id', $id);

    $id = 1; // Example record ID to delete

    $stmt->execute();
    echo "Record deleted successfully.";
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

Read (Select) With Loop

try {
          $sql = "SELECT * FROM users WHERE user_email = '$l_email' AND user_password = '$encrypted_password'";
          $stmt = $pdo->query($sql);
          $stmt->execute();

          while ($row = $stmt->fetch()) {
              // Process the retrieved data
           $value = $row['id'];
           
            echo "$new_value";
          }
        } catch (PDOException $e) {
            echo "Error: " . $e->getMessage();
        }
}

Explanation:

1. The PDO database connection code establishes a connection to your MySQL database, and it sets the error mode and fetch mode to provide useful error messages and fetch data as associative arrays.
2. The CRUD examples demonstrate how to perform basic database operations with PDO: Create (INSERT), Read (SELECT), Update (UPDATE), and Delete (DELETE).
3. Prepared statements are used to prevent SQL injection by binding values to placeholders.

Make sure to replace placeholders like your_database_name, your_username, your_password, and your_table with your actual database details and table name. Also, modify the column names and values accordingly for your specific use case.