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MVC Design Pattern

MVC Diagram

MVC Pattern Flow

Model-View-Controller architecture separates application logic into three interconnected components:

User View User Interface HTML, Forms, UI Controller Business Logic Request Handler Model Data Layer Database, APIs 1 2 3 4 User Action (clicks, form submit) Data Request (CRUD operations) Data Response (returns processed data) View Update (renders new content)

How MVC Works:

  1. User Interaction: User clicks a button or submits a form in the View
  2. Controller Processing: Controller receives the request, validates input, and decides what action to take
  3. Data Operations: Controller asks Model to fetch/update data from database or external APIs
  4. Data Response: Model returns processed data back to the Controller
  5. View Update: Controller processes the data and updates the View with new information

Benefits of MVC:

  • Separation of Concerns: Each component has a specific responsibility
  • Maintainable: Changes to one component don't affect others
  • Testable: Each layer can be tested independently
  • Reusable: Models and Controllers can be reused across different Views
  • Architectural design pattern
  • Separates application logic into three interconnected components
  • Promotes organized, maintainable code
  • Widely used in web development

  • Manages data and business logic
  • Handles database interactions
  • Contains application rules and validation
  • Manages the presentation layer
  • Displays data to users
  • Handles user interface elements
  • Acts as intermediary between Model and View
  • Processes user input
  • Controls application flow

  1. User interacts with the View (clicks, forms, etc.)
  2. Controller receives the user input
  3. Controller processes the request and interacts with Model
  4. Model performs business logic and data operations
  5. Model returns data to Controller
  6. Controller updates the View with new data
  7. View displays updated information to user

  • Each component has a specific responsibility
  • Easier to maintain and debug
  • Changes in one layer don’t affect others
  • Models can be shared across different views
  • Views can display data from multiple models
  • Controllers can be reused for similar operations

  • Each component can be tested independently
  • Mock objects can simulate dependencies
  • Unit testing becomes more straightforward
  • Different developers can work on different layers
  • Frontend and backend development can proceed in parallel
  • Clearer code organization

  • Lightweight and fast
  • Minimal setup required
  • Perfect for APIs and small web applications
  • Follows PSR standards
  • Routing system
  • Middleware support
  • Dependency injection
  • HTTP message handling

  • Provides the foundation for MVC implementation
  • Flexible architecture
  • Developers implement their own MVC structure
  • Uses controllers as route handlers
  • Routes define application endpoints
  • Middleware handles cross-cutting concerns
  • Containers manage dependencies
  • Templates render views

  • Database connections and queries
  • Data validation and sanitization
  • Business rules enforcement
  • Entity relationships
  • Keep models focused on single responsibility
  • Use proper validation
  • Handle errors gracefully
  • Implement proper database abstraction

  • Template rendering
  • HTML/JSON output generation
  • User interface components
  • Data presentation formatting
  • Keep views simple and logic-free
  • Use template engines (Twig, Smarty)
  • Separate presentation from business logic
  • Ensure responsive design

  • Handle HTTP requests
  • Coordinate between Model and View
  • Process user input
  • Manage application flow
  • Keep controllers thin
  • Delegate business logic to models
  • Handle one responsibility per action
  • Proper error handling and validation

  • Business logic lives in models
  • Controllers only coordinate
  • Easier testing and maintenance
  • Additional layer between Controller and Model
  • Handles complex business operations
  • Promotes code reuse

  • Maintain clear separation of concerns
  • Use dependency injection
  • Implement proper error handling
  • Follow naming conventions
  • Write comprehensive tests
  • Lazy loading of data
  • Efficient database queries
  • Proper caching strategies
  • Minimize controller complexity