How to use PHP and CodeIgniter framework for application development

With the popularity and development of the Internet, more and more people are beginning to develop their own websites and applications. PHP is a popular server-side programming language, and the CodeIgniter framework is an open source PHP framework that can help developers quickly build applications and improve development efficiency and code readability. This article will introduce how to use PHP and CodeIgniter framework for application development.

1. Install PHP and CodeIgniter framework

Before we start developing the application, we need to install PHP and CodeIgniter framework. If you have not installed PHP, you can download the latest version of PHP from the official website (http://www.php.net/downloads.php) and install it. In order to use the CodeIgniter framework, we need to download the latest version of the CodeIgniter framework (http://www.codeigniter.com/) and extract it to a directory on the server.

2. Creating an Application

The first step in creating an application is to create a new CodeIgniter application. We can create an application on the command line by running the following command:

php /path/to/codeigniter/framework/index.php create project_name

where project_name is the name of the application you want to create. This command will create a new project directory, which contains all the files of the CodeIgniter framework and the default configuration file.

3. Configuring the database

Most applications need to connect to the database, so we need to configure the CodeIgniter framework to connect to the database. We need to open the /application/config/database.php file and modify the following lines of code:

'hostname' => 'localhost',
'username' => 'your_username',
'password' => 'your_password',
'database' => 'your_database',

Among them, your_username represents the user name to connect to the database, your_password represents the password to connect to the database, your_database represents the name of the database you need to connect to.

4. Creating Controllers and Views

In the CodeIgniter framework, controllers are used to handle user requests and call the appropriate models and views to generate responses. We can create a new controller in the command line using the following command:

php index.php tools make_controller example

This will create a file named example.php# in the /application/controllers directory. ## controller. In the controller, we can define some methods to handle different requests, for example:

class Example extends CI_Controller {

    public function index()
    {
        $this->load->view('example');
    }

    public function welcome()
    {
        $this->load->view('welcome');
    }

}

The above code defines two methods

index and welcome, which The /application/views/example.php and /application/views/welcome.php views are loaded respectively.

Create model

In the CodeIgniter framework, models are used to handle database operations and data validation. We can create a new model in the command line using the following command:

php index.php tools make_model example_model

This will create a file named

example_model.php## in the /application/models directory #'s model. In this model, we can define some methods to handle database operations, for example: <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class='brush:php;toolbar:false;'>class Example_model extends CI_Model { public function get_data() { $query = $this-&gt;db-&gt;get('data_table'); return $query-&gt;result(); } }</pre><div class="contentsignin">Copy after login</div></div>The above code defines a method named

get_data

, which will query a method named data_table's data table and returns the query results.

Run the application

After writing the controller, view and model, we can access the application in the browser, for example:

http://yourdomain.com/index.php/example/index

The above URL will call the

index

method of the Example controller and output the /application/views/example.php view. We can also call the welcome method of the Example controller by visiting http://yourdomain.com/index.php/example/welcome and output /application/views/welcome.phpView. Summary

This article introduces how to use PHP and the CodeIgniter framework for application development. We completed a basic application development by installing PHP and the CodeIgniter framework, creating the application, configuring the database, creating controllers and views, creating models and running the application. If you want to develop applications using PHP and frameworks, the CodeIgniter framework will be a good choice.

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