PHP OOP and MySQL

Section 1: Lab: Setting Up a Professional PHP 8.5 Project

• Why OOP: the problems with procedural code as a system grows
• Run PHP 8.5 and MySQL with Docker Compose
• Create a project with Composer and PSR-4 autoloading
• declare(strict_types=1) and the PER Coding Style
• Lab: a starter project used in every lab of the course

Section 2: Classes, Objects and Encapsulation

• Classes, objects, typed properties and methods
• Constructor promotion, destructors and visibility
• readonly properties and readonly classes
• Property hooks and asymmetric visibility such as private(set) in PHP 8.4 and later
• Lab: product and price classes that reject invalid values on creation

Section 3: Lab: Inheritance, Abstract Classes and Interfaces

• Inheritance with extends, parent and overriding
• final classes and final methods
• Abstract classes versus interfaces, and how to choose
• Polymorphism through interfaces
• Lab: a shipping cost calculator with several methods

Section 4: Traits, Static Members and Enums

• Traits for sharing code, and their pitfalls
• Static properties, static methods and late static binding
• Pure and backed enums with methods and interfaces
• match expressions and first-class callables
• Lab: order statuses with enums

Section 5: Namespaces, Exceptions and Value Objects

• Organising code with namespaces and use
• Building your own exception hierarchy and handling errors systematically
• Immutable value objects and copying them with clone with in PHP 8.5
• The pipe operator and the #[NoDiscard] attribute new in PHP 8.5
• Lab: money and email value objects with exceptions

Section 6: Lab: Connecting to MySQL with Object-Oriented PDO

• A PDO connection class with utf8mb4 and exception error mode
• Prepared statements with named parameters to prevent SQL injection
• Mapping results to objects and hydrating data
• Transactions with beginTransaction, commit and rollBack
• Lab: save an order and its items in a single transaction

Section 7: Repositories, Active Record and Data Mapper

• Separating data access from business logic
• A repository interface and its MySQL implementation
• Active Record versus Data Mapper through the ideas behind Eloquent and Doctrine ORM
• When to use an ORM and when to write SQL yourself
• Lab: product and order repositories

Section 8: SOLID Principles in PHP Code

• Single responsibility and open/closed
• Liskov substitution and interface segregation
• Dependency inversion and depending on interfaces rather than classes
• Common code smells and refactoring step by step
• Lab: refactor procedural code into OOP following SOLID

Section 9: Dependency Injection and Containers

• Constructor injection versus creating objects inside a class
• PSR-11 containers and autowiring
• Binding interfaces to implementations and swapping them per environment
• Lab: wire services, repositories and a logger through a container

Section 10: Lab: Unit Testing with PHPUnit 13

• Install PHPUnit with Composer and structure the tests
• Write tests with attributes such as #[Test] and #[DataProvider]
• Test doubles with createStub and createMock
• Testing repositories against a test database
• Check code with PHPStan and format it with PHP CS Fixer

Section 11: Creational Patterns

• What design patterns are, and using them without overcomplicating code
• Singleton, and why modern code usually prefers dependency injection
• Factory Method and Simple Factory
• Builder for objects with many configuration options
• Lab: several notification channels created through a factory

Section 12: Lab: Structural Patterns

• Adapter for connecting external libraries or services
• Decorator for adding behaviour without changing the original class
• Composite for hierarchical data such as product categories
• Facade for hiding the complexity of a subsystem
• Lab: an adapter that supports several payment providers

Section 13: Behavioral Patterns

• Strategy for swapping calculations such as different discounts
• Observer and event dispatchers following the PSR-14 idea
• Command for separating an action from the code that triggers it
• Template Method and State in brief
• Lab: discounts with Strategy and order notifications with Observer

Section 14: MVC and the Front Controller

• The MVC structure and the roles of model, view and controller
• A front controller and a simple router
• Requests, responses and middleware following the PSR-7 and PSR-15 ideas
• Views that escape every value to prevent XSS
• Comparing the hand-built structure with Laravel and Symfony

Section 15: Workshop: Capstone Object-Oriented Order Management System

• Design a class diagram and split the system into layers
• Build it with repositories, services, suitable patterns and dependency injection
• Test the key business logic, and use an AI assistant to review the code while checking it yourself
• Present the work, review the design together and plan next steps towards Laravel