The document compares the directory structures and MVC implementation between CodeIgniter 3 and CodeIgniter 4. Some key differences include CodeIgniter 4 using namespaces for classes, updating the directory structure of application and system folders, and implementing an ORM for models to work with databases rather than using the query builder as in CodeIgniter 3. The index.php file is also updated to bootstrap the framework differently in CodeIgniter 4.
The document contains code snippets and documentation about CakePHP, an open-source PHP web framework. It includes PHP code for retrieving data from a database based on a search keyword and displaying the results. It also discusses the model-view-controller approach used in CakePHP and configuring CakePHP to work without URL rewriting. The code examples demonstrate basic usage of CakePHP for building a web application.