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PHP · Question Set
Real-World Scenarios & Tricky Questions interview questions for placements and exams.
Questions
15
Included in this set
Subject
PHP
Explore more sets
Difficulty
Mixed
Level of this set
Go through each question and its explanation. Use this set as a focused practice pack for PHP.
Prepared statements separate SQL logic from user input. This prevents attackers from injecting malicious SQL through form inputs or URLs.
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?');Use caching for static data, load balancing across multiple servers, database optimization, asynchronous job queues, and CDNs for assets. Stateless design helps distribute load efficiently.
Tools like Xdebug and Laravel Telescope help inspect runtime errors, variable states, and queries. Logging with Monolog and using PHP’s built-in error_log also simplify debugging and monitoring in real projects.
A CSRF token is a random, unique value added to each form or request. The server verifies it to ensure the request came from a trusted source, preventing forgery attacks.
Escaping output ensures user input is shown as plain text instead of executable HTML or JavaScript. This prevents Cross-Site Scripting attacks.
echo htmlspecialchars($input, ENT_QUOTES);
The password_hash function automatically salts and hashes passwords using strong algorithms like bcrypt, making stored passwords secure.
password_hash('mypassword', PASSWORD_DEFAULT);Using HTTPS encrypts session data in transit, while regenerating session IDs after login prevents attackers from reusing old session tokens.
session_regenerate_id(true);
In production, sensitive error messages should not be visible to users. Instead, errors should be logged securely for developers to review later.
ini_set('display_errors',0); ini_set('log_errors',1);The .env file contains sensitive information like API keys and database credentials. It should never be shared or committed to version control.
API keys are unique identifiers used to authenticate and track client access to an API. They help control usage and prevent unauthorized access.
Use caching mechanisms like OPCache, minimize database queries, reuse database connections, avoid nested loops, and leverage built-in PHP functions instead of manual logic. Using the latest PHP version also improves execution speed.
Always sanitize user input, escape output, use prepared statements for database queries, hash passwords, disable display_errors in production, validate file uploads, and keep the PHP version updated for latest security patches.
If not validated, malicious files like PHP shells can be uploaded and executed. To secure uploads, restrict file types, limit file sizes, rename files on upload, and store them outside the public web root.
Always use environment variables for secrets, run composer install with optimized autoload, enable caching, compress assets, set correct file permissions, and monitor logs. Use CI/CD pipelines for safe, repeatable deployments.
Check PHP version differences, missing extensions, incorrect file permissions, or case-sensitive filenames on Linux. Reviewing logs and environment configuration usually reveals the mismatch causing failure.
For complete preparation, combine this set with full subject-wise practice for PHP. You can also explore other subjects and sets from the links below.