Building Your First PHP CRUD Application

CRUD covers validated create, read, update and delete operations backed by prepared SQL.

What It Does and When to Use It

Separate business logic, input handling and rendering at a clearly identified boundary. Direct PHP code exposes the underlying operation clearly; a framework can supply lifecycle hooks, dependency wiring and retries.

Requirements, Inputs and Expected Behavior

Confirm the runtime, extension, environment variables, and permissions before running the examples in production. Require CSRF protection and authorization for state-changing routes; validate ownership.

Example 1: Basic Operation

Separate business logic, input handling and rendering at a clearly identified boundary.

<?php
$pdo = new PDO('sqlite::memory:', options:[PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE tasks (id INTEGER PRIMARY KEY, title TEXT NOT NULL)');
$pdo->prepare('INSERT INTO tasks (title) VALUES (?)')->execute(['Read docs']);
print_r($pdo->query('SELECT id,title FROM tasks')->fetchAll(PDO::FETCH_ASSOC));

Example 2: Behavior and Validation

Use the front controller to select responses while keeping routing separate from models.

<?php
$path=parse_url($_SERVER['REQUEST_URI']??'/',PHP_URL_PATH);
if ($path==='/health') { header('Content-Type: application/json'); echo json_encode(['status'=>'ok']); }
else { http_response_code(404); echo 'Not found'; }

Practical Example: Application Use

Render a trusted template path with controlled data; never derive template paths from user input.

<?php
function render(string $template, array $data): string {
    extract($data, EXTR_SKIP); ob_start();
    try { require $template; return (string)ob_get_clean(); }
    catch(Throwable $e) { ob_end_clean(); throw $e; }
}

Important Behavior and Edge Cases

The second example highlights: Use the front controller to select responses while keeping routing separate from models. The practical example adds: Render a trusted template path with controlled data; never derive template paths from user input.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• CRUD covers validated create, read, update and delete operations backed by prepared SQL.
• Render a trusted template path with controlled data; never derive template paths from user input.
• Choose based on deployment requirements and verify actual behavior rather than assuming defaults.