Suggest an editImprove this articleRefine the answer for “How does MVC provide separation of concerns?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)The **MVC (Model-View-Controller)** pattern provides **separation of concerns** because **each component is isolated** and plays a **strictly limited role** in the chain of data processing and user interaction. **Key point:** MVC divides responsibility so that each component does only "its own job" - this lowers the dependency between parts of the application and simplifies testing, extension, and maintenance.Shown above the full answer for quick recall.Answer (EN)ImageThe **MVC (Model-View-Controller)** pattern provides **separation of concerns** because **each component is isolated** and plays a **strictly limited role** in the chain of data processing and user interaction. --- ### 1. **Model** - isolates data and business logic - Is responsible only for **what happens in the system**: storage, processing, and rules. - Does not know how this data will be displayed or who requested it. - All the "what is and is not allowed" logic is concentrated here. *Example:* the method `withdraw(amount)` checks the balance and deducts money without caring where the request came from - a website or a mobile app. **Conclusion:** data and logic do not depend on the interface. --- ### 2. **View** - isolates display - Is responsible only for **how the information looks**. - Receives already-prepared data and outputs it to the user. - Contains no logic for processing or changing data. *Example:* an HTML template simply displays `{{ user.name }}`; it does not know how this user was found. **Conclusion:** the interface can be changed without rewriting business logic. --- ### 3. **Controller** - manages the flow - Is a mediator between the user, the model, and the view. - Receives input, decides what to do, and coordinates the interaction of the layers. - Does not store data and is not responsible for displaying it. *Example:* the controller handles the `GET /users/5` request, calls the method `UserModel.find(5)`, and passes the result to `profile.html`. **Conclusion:** the controller manages but does not interfere with other components' responsibilities. --- ### 4. **How this works together** ```javascript [User] ↓ input [Controller] - decides what to do ↓ [Model] - processes data and business logic ↓ [View] - shows the result ``` --- ### 5. **The result of the separation** | Component | Responsible for | Not involved in | |---|---|---| | **Model** | Data, business rules | Interface, routing | | **View** | Display | Calculations, data storage | | **Controller** | Flow control, coordination | Display, business rules | --- **Summary:** > MVC divides responsibility so that each component does only "its own job". > This lowers the dependency between parts of the application and simplifies testing, extension, and maintenance - the view can be changed without touching the logic, or the database can be changed without rewriting the interface.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.