PHP, Laravel, Git IQ - DEV Community

This comprehensive collection of technical interview questions covers essential topics for PHP and Laravel developers, from fundamental programming concepts to advanced framework features and development workflows.

PHP IQ - Part 01

Core PHP Concepts

Method Overloading & Overriding

• Method overloading: PHP doesn't support traditional overloading but uses magic methods like __call()
• Method overriding: Child classes redefine parent class methods
• Used for polymorphism and extending functionality

Traits

• Code reuse mechanism in PHP
• Allows horizontal code sharing across unrelated classes
• Prevents multiple inheritance issues
• Used for common functionality like logging, validation

OOP Principles in PHP

• Encapsulation: Data hiding through access modifiers
• Inheritance: Class hierarchy and code reuse
• Polymorphism: Multiple forms of methods
• Abstraction: Interface definition without implementation

Abstract, Interface, Trait, Namespace

• Abstract classes: Base classes with incomplete implementation
• Interfaces: Contract definition for classes
• Traits: Horizontal code reuse
• Namespaces: Code organization and conflict prevention

Require vs Include

• require: Fatal error if file not found
• include: Warning if file not found
• require_once/include_once: Prevents multiple inclusions

Multiple vs Multilevel Inheritance

• Multiple inheritance: Class inherits from multiple parents (not supported in PHP)
• Multilevel inheritance: Chain of inheritance (A → B → C)

Laravel IQ - Level 1 - Part 1

Framework Fundamentals

Laravel Framework

• PHP MVC framework for web applications
• Built-in features: routing, authentication, caching, queues
• Expressive syntax and developer-friendly tools

Middleware

• HTTP request filtering mechanism
• Runs before/after request reaches controller
• Used for authentication, CORS, logging, rate limiting

Eloquent ORM

• Active Record implementation
• Database table as classes, rows as objects
• Relationships, query building, model events

CSRF Token

• Cross-Site Request Forgery protection
• Token validation for state-changing requests
• Prevents unauthorized form submissions

Events & Listeners

• Observer pattern implementation
• Decoupled event handling
• Used for logging, notifications, data processing

Dependency Injection

• Service container manages class dependencies
• Automatic injection through constructor or method
• Promotes loose coupling and testability

Queues

• Background job processing
• Asynchronous task execution
• Improves response time and user experience

Service Provider

• Service container bootstrapping
• Package registration and configuration
• Application service registration

Blade Template Engine

• Laravel's templating engine
• Clean syntax with control structures
• Template inheritance and sections

API Route Creation

• Route definition with HTTP methods
• Resource controllers for CRUD operations
• Middleware for authentication and rate limiting

Laravel IQ - Level 1 - Part 2

Advanced Laravel Concepts

MVC Architecture

• Model: Data and business logic
• View: Presentation layer
• Controller: Request handling and response
• Laravel's implementation of MVC pattern

Routing

• URL to controller mapping
• Route parameters and constraints
• Named routes and middleware

Artisan Commands

• CLI tool for Laravel
• Code generation, database migrations, testing
• Custom command creation

Facade

• Static interface to underlying classes
• Service container access
• Clean syntax for complex operations

Service Container

• Dependency injection container
• Service binding and resolution
• Application service management

Validation

• Request data validation
• Form request classes
• Custom validation rules

Blade @yield and @section

• Template inheritance
• Content sections definition
• Layout composition

Soft Delete

• Logical deletion without data loss
• deleted_at timestamp column
• Query scope for excluding deleted records

Cookie vs Session

• Cookie: Client-side storage
• Session: Server-side storage with client reference
• Security and persistence differences

Accessor & Mutator

• Model attribute transformation
• getFooAttribute() and setFooAttribute()
• Data formatting and validation

Policy & Gate

• Authorization mechanisms
• Policy: Class-based authorization
• Gate: Closure-based authorization
• Resource-based permissions

Job & Queue

• Job: Unit of work
• Queue: Job storage and processing
• Background processing for heavy tasks

Repository Pattern

• Data access abstraction
• Business logic separation
• Testability and maintainability

Pivot Table

• Many-to-many relationship table
• Additional attributes on relationships
• Intermediate table management

Observers

• Model event handling
• Centralized event logic
• Multiple model event management

Resource Controllers

• RESTful controller methods
• Standard CRUD operations
• Resource route generation

HTTP Middleware Creation

• Custom middleware implementation
• Request/response modification
• Application-specific filtering

Aggregates Functions

• Database aggregation: count(), max(), min(), avg()
• Query optimization
• Data summarization

API Authentication

• Passport: OAuth2 server
• Sanctum: API token authentication
• Token-based authentication methods

Laravel Mix

• Asset compilation and versioning
• Webpack integration
• CSS/JS preprocessing

Caching

• Data storage for performance
• Multiple cache drivers
• Cache invalidation strategies

File Storage System

• Local and cloud storage
• Flysystem integration
• File upload and management

Event Broadcasting

• Real-time event delivery
• WebSocket integration
• Client-side event handling

Rate Limiting

• Request frequency control
• User and IP-based limits
• API protection mechanism

Seeder & Factory

• Database seeding
• Test data generation
• Model factory creation

Relationship Methods

• hasOne, belongsTo, hasMany, belongsToMany
• Relationship definition and usage
• Eager loading optimization

Form Request Validation

• Dedicated validation classes
• Authorization and validation
• Clean controller methods

Job Batching

• Multiple job grouping
• Batch processing and monitoring
• Job dependency management

Shallow vs Deep Copy

• Shallow copy: Reference copying
• Deep copy: Complete object duplication
• Memory and performance implications

Laravel IQ - Level 1 - Part 3

Advanced Laravel Topics

Service Provider Dependency Injection

• Service container binding
• Constructor injection
• Interface to implementation mapping

Multitenancy Implementation

• Multi-tenant architecture
• Database isolation strategies
• Tenant-specific data handling

Laravel Telescope

• Application debugging assistant
• Request, database, and cache monitoring
• Development tool for performance analysis

Laravel Horizon

• Queue monitoring dashboard
• Redis queue management
• Job monitoring and metrics

Custom Blade Directive

• Directive creation
• Template extension
• Custom syntax implementation

Redis Cache Usage

• High-performance caching
• Data structure operations
• Session and cache storage

Scout & Algolia Search

• Full-text search implementation
• Third-party search service integration
• Search optimization

Advanced Security Middleware

• Custom security implementations
• Request validation and filtering
• Application protection mechanisms

Chunking

• Large dataset processing
• Memory-efficient operations
• Batch data handling

Data Encryption

• Data security implementation
• Encryption and decryption
• Secure data storage

Laravel Dusk

• Browser automation testing
• End-to-end testing
• User interaction simulation

Dynamic Rate Limiting

• Flexible rate limiting strategies
• User-specific limits
• Adaptive rate control

Lazy vs Eager Loading

• Performance optimization
• Query execution differences
• N+1 query problem solution

Custom Exception Handling

• Exception handling customization
• Error response formatting
• Application-specific error management

Package Development

• Package creation and distribution
• Service provider registration
• Package configuration

Multi-Authentication

• Multiple user types
• Different authentication guards
• Role-based access control

Database Transactions

• Atomic operations
• Rollback and commit
• Data consistency management

Livewire

• Dynamic interfaces without JavaScript
• Server-side rendering
• Real-time updates

API Versioning

• API evolution management
• Version-specific endpoints
• Backward compatibility

Cache Invalidation

• Cache update strategies
• Data consistency
• Performance optimization

cURL Implementation

• HTTP client usage
• API communication
• External service integration

Database Transactions

• db::transaction, commit, rollback
• Transaction management
• Error handling and recovery

Service Provider vs Service Container

• Service provider: Service registration
• Service container: Service resolution
• Application service management

REST vs RESTful API

• REST: Architectural style
• RESTful: REST principle implementation
• API design patterns

REST Principles & Best Practices

• Stateless communication
• Cacheable responses
• Uniform interface

Laravel Lifecycle

• Application bootstrapping
• Request lifecycle
• Service container initialization

Fillable & Guard

• Mass assignment protection
• Attribute whitelisting/blacklisting
• Security implementation

Laravel IQ - Level 1 - Part 4

BST & Advanced Topics

Solid Principle in PHP

• Single Responsibility
• Open/Closed
• Liskov Substitution
• Interface Segregation
• Dependency Inversion

Load Balancer

• Traffic distribution
• High availability
• Performance optimization

Multiple Inheritance Support

• PHP doesn't support multiple inheritance
• Traits as alternative
• Interface implementation

Mixins vs Composer

• Mixins: Code sharing
• Composer: Dependency management
• Package management differences

HTTP vs HTTPS

• HTTP: Unencrypted communication
• HTTPS: Encrypted communication
• Security and trust differences

Redis Usage

• In-memory data structure store
• Caching and session storage
• Real-time data processing

Stateful vs Stateless

• Stateful: Session-based
• Stateless: Token-based
• Scalability implications

JavaScript Prototype & Closure

• Prototype: Object inheritance
• Closure: Function scope preservation
• Memory management

AJAX Steps

• XMLHttpRequest creation
• Request configuration
• Response handling
• Error management

Database Indexing

• Performance optimization
• Query speed improvement
• Storage overhead

Cross-Site Scripting & Docker

• XSS: Security vulnerability
• Docker: Containerization
• Development and deployment

Algorithm for 3 Million Products

• Database indexing strategies
• Query optimization
• Search algorithm selection

CSRF Token Generation

• Token creation and validation
• Session storage
• Security implementation

SMS Campaign for 10 Million Users

• Queue-based processing
• Rate limiting
• Error handling and retry

Laravel IQ - Level 1 - Part 5

Performance & Architecture

Real-time Menu Updates

• Cache invalidation
• WebSocket notifications
• Client-side updates

Redis Configuration

• Shared hosting vs VPS vs AWS
• Environment configuration
• Production setup

Data Display Strategies

• Chunking vs AJAX loading
• Memory management
• Performance optimization

Facebook-style Infinite Scroll

• AJAX-based loading
• Scroll event handling
• Performance considerations

SaaS System for 1 Million Users

• Scalability architecture
• Database optimization
• Performance monitoring

Database Join Performance

• Query optimization
• Index usage
• O(log n) complexity

Multi-database Joins

• Cross-database queries
• Microservices integration
• Data consistency

Rate Limiting Data

• User-specific limits
• IP-based restrictions
• Adaptive rate control

Middleware Priority

• Execution order definition
• Route-specific middleware
• Global middleware

Sanctum Token Storage

• Database storage
• Security considerations
• Token management

Session Types

• File-based sessions
• Database sessions
• Redis sessions

Database Query Optimization

• Query analysis
• Index optimization
• Performance improvement

API Design for Millions of Requests

• Load balancing
• Caching strategies
• Database optimization

API Postman vs Browser Issues

• CORS configuration
• Headers and authentication
• Environment differences

Microservices Performance

• Network overhead
• Service communication
• Performance trade-offs

Laravel VPS Deployment

• Server configuration
• Environment setup
• Security implementation

URL Request Flow

• Browser request process
• DNS resolution
• Server response

503 Server Error

• Server overload
• Maintenance mode
• Recovery strategies

JWT Payload

• Public vs private claims
• Token structure
• Security considerations

Default Service Providers

• Laravel core services
• Package registration
• Application bootstrapping

REST API Usage

• Architectural benefits
• Standardization
• Client-server communication

Laravel Batch

• Job grouping
• Batch processing
• Monitoring and management

TDD in Laravel

• Test-driven development
• Unit and feature tests
• Development workflow

SOLID Principle Implementation

• Single responsibility
• Open/closed principle
• Dependency injection

Laravel IQ - Part-01

PHP & Laravel Fundamentals

GET vs POST

• GET: Data in URL, cacheable
• POST: Data in body, secure
• Use case differences

Route Model Binding

• Automatic model resolution
• Route parameter binding
• Clean controller methods

Polymorphic Relationship

• Multiple model relationships
• Single interface
• Flexible data modeling

Middleware Priority

• Execution order
• Route-specific middleware
• Global middleware

Eager vs Lazy Loading

• Performance optimization
• Query execution
• N+1 problem solution

with() vs load()

• Eager loading differences
• Relationship loading
• Performance implications

Pagination

• Data set division
• Page navigation
• Performance optimization

Laravel Reverb & Echo

Real-time Communication

WebSocket

• Persistent connection
• Real-time communication
• HTTP alternative

Laravel Reverb

• WebSocket server
• Pusher alternative
• Real-time features

Laravel Echo

• Client-side WebSocket
• Event handling
• Real-time updates

Channel Types

• Public, private, presence
• Authentication requirements
• Use case differences

ShouldBroadcast Interface

• Event broadcasting
• Queue integration
• Real-time delivery

broadcast() vs event()

• Direct vs queued broadcasting
• Performance implications
• Use case differences

SerializesModels Trait

• Model serialization
• Queue job handling
• Memory optimization

Queue for Broadcasting

• Background processing
• Performance improvement
• Real-time delivery

Private Channel Authentication

• User authentication
• Channel authorization
• Security implementation

broadcastOn() vs broadcastWith() vs broadcastAs()

• Channel definition
• Data broadcasting
• Event naming

.toOthers()

• Event exclusion
• Client-specific delivery
• Real-time updates

Redis Queue

• Queue storage
• Job processing
• Performance optimization

Ajax Double Call Issue

• Event handling
• Request prevention
• Performance improvement

Supervisor

• Process management
• Queue worker management
• Production reliability

ShouldBroadcastNow vs ShouldBroadcast

• Immediate vs queued broadcasting
• Performance implications
• Use case differences

Unread Message Count

• Real-time updates
• Database synchronization
• Client-side display

.env Reverb Config

• Environment configuration
• WebSocket server setup
• Production deployment

Nginx Reverb Proxy

• WebSocket proxy
• Load balancing
• Security implementation

Real-time Order Status

• Event broadcasting
• Database updates
• Client-side display

Production Checks

• Performance monitoring
• Security validation
• Error handling

Reverb Network

• WebSocket network
• HTTP vs WebSocket
• Real-time communication

whisper & listenForWhisper

• Private communication
• Client-server messaging
• Real-time updates

WebSocket in PHP

• Server implementation
• Client connection
• Real-time communication

API IQ - Level 1 - Part 1

API Fundamentals

API Definition

• Application Programming Interface
• Software communication
• Data exchange

REST API

• Representational State Transfer
• Architectural style
• HTTP-based communication

REST vs SOAP API

• REST: Lightweight, flexible
• SOAP: Standardized, secure
• Use case differences

HTTP Methods

• GET, POST, PUT, DELETE
• Resource operations
• RESTful principles

Laravel API Requirements

• Route definition
• Controller creation
• Response formatting

Laravel Sanctum

• API token authentication
• SPA authentication
• Mobile app authentication

API Rate Limiting

• Request frequency control
• User-based limits
• Security implementation

Laravel API Resource

• Response formatting
• Data transformation
• API consistency

JWT (JSON Web Token)

• Token-based authentication
• Stateless communication
• Security implementation

CORS (Cross-Origin Resource Sharing)

• Cross-domain requests
• Security headers
• Browser compatibility

CSRF (Cross-Site Request Forgery)

• Security vulnerability
• Protection mechanisms
• Token validation

Laravel API Testing Tools

• Postman
• PHPUnit
• Automated testing

PHPUnit Test Example

• Test case creation
• API endpoint testing
• Response validation

HTTP Status Codes

• Response codes
• Client/server errors
• Success responses

Status Code Categories

• 1xx: Informational
• 2xx: Success
• 3xx: Redirection
• 4xx: Client Error
• 5xx: Server Error

Common API Status Codes

• 200: OK
• 201: Created
• 400: Bad Request
• 401: Unauthorized
• 404: Not Found
• 500: Internal Server Error

REST vs GraphQL

• REST: Multiple endpoints
• GraphQL: Single endpoint
• Query flexibility

API Versioning

• Version management
• Backward compatibility
• API evolution

JWT Working

• Token creation
• Payload encoding
• Verification process

OAuth 2.0

• Authorization framework
• Token-based access
• Security implementation

Laravel API Response Caching

• Cache storage
• Response optimization
• Performance improvement

Laravel API Security

• Authentication
• Authorization
• Input validation

Laravel API Authentication Methods

• Token-based
• OAuth
• Session-based

Laravel Sanctum Working

• Token generation
• Authentication process
• Security implementation

Laravel API Performance

• Caching strategies
• Database optimization
• Code efficiency

Laravel API HATEOAS

• Hypermedia as the Engine of Application State
• API discoverability
• Client-server communication

Laravel API WebSocket

• Real-time communication
• Event broadcasting
• Client-server updates

Database - Level 1 - Part 1

Database Fundamentals

SQL Definition

• Structured Query Language
• Database management
• Data manipulation

SELECT, INSERT, UPDATE, DELETE

• Data retrieval
• Data insertion
• Data modification
• Data deletion

WHERE vs HAVING

• WHERE: Row filtering
• HAVING: Group filtering
• Query optimization

GROUP BY Usage

• Data aggregation
• Group operations
• Query organization

Index Definition

• Performance optimization
• Query speed improvement
• Storage overhead

Normalization

• Data organization
• Redundancy elimination
• Database design

1NF, 2NF, 3NF

• First Normal Form
• Second Normal Form
• Third Normal Form
• Database design principles

Primary vs Unique Key

• Primary: Table identifier
• Unique: Unique constraint
• Nullability differences

Foreign Key

• Table relationship
• Referential integrity
• Data consistency

ACID Properties

• Atomicity
• Consistency
• Isolation
• Durability
• Transaction management

SQL JOIN

• Table combination
• Relationship queries
• Data retrieval

INNER JOIN

• Matching rows only
• Common data
• Query optimization

LEFT vs RIGHT JOIN

• LEFT: All left table rows
• RIGHT: All right table rows
• Data inclusion differences

FULL OUTER JOIN

• All rows from both tables
• Complete data set
• Query results

SELF JOIN

• Table self-reference
• Hierarchical data
• Query complexity

View vs Materialized View

• View: Virtual table
• Materialized: Physical table
• Performance differences

Stored Procedure vs Function

• Procedure: Multiple statements
• Function: Single return value
• Usage differences

Index Working

• B-tree structure
• Query optimization
• Performance impact

Query Optimization

• Execution plan analysis
• Index usage
• Performance improvement

Database Sharding vs Replication

• Sharding: Data distribution
• Replication: Data copying
• Scalability differences

Deadlock Handling

• Resource contention
• Prevention strategies
• Resolution methods

ORM Performance Issues

• Abstraction overhead
• Query optimization
• Performance considerations

Eager vs Lazy Loading

• Performance optimization
• Query execution
• N+1 problem solution

Transaction Isolation Levels

• Read uncommitted
• Read committed
• Repeatable read
• Serializable
• Data consistency

EXPLAIN Command

• Query execution plan
• Performance analysis
• Optimization guidance

SQL Categories

• DDL: Data Definition Language
• DML: Data Manipulation Language
• DCL: Data Control Language
• TCL: Transaction Control Language

Constraints

• Data integrity
• Rule enforcement
• Database design

GROUP BY Examples

• Data aggregation
• Query organization
• Result grouping

Query Execution Order

• Logical processing
• Performance implications
• Query optimization

SELECT Execution

• Last execution
• Query optimization
• Performance considerations

TRUNCATE vs DELETE

• TRUNCATE: Fast, no rollback
• DELETE: Slower, rollback possible
• Use case differences

DROP vs TRUNCATE

• DROP: Table removal
• TRUNCATE: Data removal
• Database impact

Git, GitHub, PR & Version Control

Version Control Fundamentals

Version Control System (VCS)

• Code history management
• Collaboration support
• Change tracking

Version Control Need

• Team collaboration
• Change history
• Code backup

Problems Without Version Control

• File overwriting
• History loss
• Collaboration issues

Centralized vs Distributed VCS

• Centralized: Single repository
• Distributed: Local copies
• Collaboration differences

Git Definition

• Distributed version control
• Open source
• Industry standard

Git vs GitHub

• Git: Version control system
• GitHub: Hosting platform
• Service differences

Git Without GitHub

• Local repositories
• Self-hosted solutions
• Alternative platforms

Repository Definition

• Code storage
• Version history
• Project management

Local vs Remote Repository

• Local: Developer machine
• Remote: Server storage
• Collaboration mechanism

Git Workflow

• Development process
• Branch management
• Code integration

git init

• Repository creation
• Version control start
• Project initialization

git clone

• Repository copying
• Remote to local
• Project setup

git status

• Working directory state
• Changes tracking
• Repository status

git add

• File staging
• Change tracking
• Commit preparation

git commit

• Change recording
• Version creation
• History maintenance

Good Commit Message

• Clear description
• Context provision
• Team communication

git log

• Commit history
• Version tracking
• Repository timeline

git diff

• Change comparison
• File differences
• Code review

git reset

• Change undoing
• Repository state
• History modification

git revert

• Change reversal
• New commit creation
• History preservation

Branch Definition

• Development line
• Feature isolation
• Code organization

Branch Need

• Parallel development
• Feature isolation
• Code stability

Default Branch

• Main development branch
• Project starting point
• Code integration

git checkout -b

• Branch creation
• Branch switching
• Development start

Merge Definition

• Branch combination
• Code integration
• Development completion

Merge Conflict

• Code contradiction
• Resolution needed
• Development process

Conflict Resolution

• Manual editing
• Code selection
• Integration completion

Fast-forward Merge

• Linear history
• Simple integration
• Branch combination

Rebase

• History rewriting
• Branch integration
• Linear development

Cherry-pick

• Specific commit selection
• Branch application
• Code transfer

Remote Repository

• Server storage
• Collaboration platform
• Code sharing

origin

• Default remote name
• Repository reference
• Connection point

git push

• Local to remote
• Code sharing
• Collaboration

git pull

• Remote to local
• Code update
• Synchronization

git fetch vs pull

• Fetch: Download only
• Pull: Download and merge
• Update differences

Fork Definition

• Repository copy
• Independent development
• Contribution mechanism

Fork Need

• Project contribution
• Independent development
• Code experimentation

Pull Request (PR)

• Code contribution
• Review process
• Integration request

PR Need

• Code review
• Quality assurance
• Collaboration

PR Workflow

• Development process
• Review cycle
• Integration steps

Code Review

• Quality assurance
• Knowledge sharing
• Code improvement

PR Merge Types

• Merge commit
• Squash merge
• Rebase merge

Squash Merge

• Multiple commits to one
• Clean history
• Integration method

Draft PR

• Work in progress
• Review preparation
• Development stage

.gitignore

• File exclusion
• Repository management
• Sensitive data protection

Laravel gitignore Files

• Environment files
• Cache directories
• Sensitive data

.env Git Exclusion

• Security protection
• Environment specificity
• Configuration management

Git Stash

• Change temporary storage
• Context switching
• Development flexibility

git stash pop

• Change restoration
• Stash removal
• Development continuation

Git Tag

• Version marking
• Release management
• Code reference

Semantic Versioning

• Version numbering
• Release management
• Compatibility indication

Git Hooks

• Event triggers
• Automation
• Development workflow

Hotfix Branch

• Critical bug fixes
• Production issues
• Quick resolution

Feature Branch

• New functionality
• Development isolation
• Code organization

Professional Git Workflow

• Team collaboration
• Code quality
• Development process

Git Slash Command

• Command efficiency
• Workflow optimization
• Development speed

Multiple User Code Merge

• Branch combination
• Conflict resolution
• Integration process