# Models, Views and Controllers

## What is MVC?

MVC (Model-View-Controller) is a design pattern used in software development, especially for web applications. It separates an application into three main components:

* Model – Manages data and business logic.
* View – Handles the user interface (UI) and presentation.
* Controller – Acts as a bridge between the Model and View, processing user inputs.

## How it works?

1. **User requests a page (URL):** The request is sent to a **Controller**.
2. **Controller processes the request:** It may interact with a **Model** to get or update data.
3. **Model handles data:** The Model retrieves, updates, or processes data from the database.
4. **Controller passes data to the View:** The View formats and displays the data to the user.
5. **User sees the updated page:** The final output (HTML, JSON, etc.) is sent to the browser                                                                    

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## The Components

### Models

* Represents data and defines how it is processed.
* Communicates with the database.
* Does not directly interact with the View.

Functions in [BaseModel](/documents/core/basemodel.md)

**`__construct()`**: Automatically called when an object is instantiated. It is typically used to establish a database connection or initialize important class properties.

**`_schema()`**: Defines the structure of the database table by specifying columns and their data types.

**`_table()`**: Returns the name of the database table that the model corresponds to, making queries more flexible and maintainable.

**`_columns()`**: Specifies the list of columns that can accept data during insert or update operations.

**`row()`**: Fetches a single record from the specified table based on the given search conditions.

**`list()`**: Fetches multiple records from the table based on specified conditions, with options for sorting and limiting the number of returned records.

**`listpaging()`**: Fetches paginated data, allowing large datasets to be divided into manageable pages for better control and display.

**`listfieldpaging()`**: Obtains data from specific table columns with pagination support, optimizing query performance and data display.

**`add()`**: Inserts a new record into the specified table with the provided data, ensuring validation before storage.

**`set()`**: Updates one or more records in the table based on specified conditions, ensuring that only valid fields are modified.

**`del()`**: Deletes one or more records from the table based on the provided conditions.

**`query()`**: Executes a custom SQL query with provided parameters, allowing for extended query capabilities beyond the default CRUD operations.

**`lastInsertId()`**: Gets the ID of the most recently inserted record in the table.

**`count()`**: Counts the number of records in the specified table based on given conditions.

Explore more about [Models](/documents/models.md)

### **Views**

* Displays the data provided by the Controller.
* Contains HTML, CSS, JavaScript, and minimal PHP.
* Should not contain business logic.

Explore more about  [Views & Templates](/documents/views-and-templates.md)

### **Controllers**

* Processes user input and interacts with the Model.
* Sends the processed data to the View.
* Acts as the middleman between Model and View.

Functions in [BaseController](/documents/core/basecontroller.md)

* **`data()`**: Stores and retrieves internal class data. It is used to temporarily store information for use in other methods.
* **`render()`**: Displays content using a predefined layout. This method is useful for managing webpage rendering in an MVC framework.
* **`json()`**: Returns data in JSON format. It is commonly used to provide data for APIs or AJAX requests.
* **`success()`**: Returns a JSON response for successful operations. This is typically used for API responses when a request is successfully completed.
* **`error()`**: Returns a JSON response for errors. It helps send API error responses when an issue occurs in the system.
* **`get_success()`**: Returns a success response as an array. This method is useful for processing API responses internally before sending them to the client.
* **`get_error()`**: Returns an error response as an array. It is used to check errors during processing before sending a response.

Explore more about [Controllers](/documents/controllers.md)


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