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

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

__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.

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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

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

• 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.

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