Dynamic instantiation
In CI, the import of components and the execution of functions are only executed when requested, not in the global scope. It is not assumed that the system requires any resources other than minimal core resources, so the default system is very lightweight. The events triggered by HTTP requests, and the controllers and views you design will determine when they are referenced.
Loose coupling
Coupling refers to the degree of correlation between the components of a system. The fewer components that depend on each other, the better the reusability and flexibility of the system. CI is a loosely coupled system
Component specificity
Specificity means that the component has a very small focused goal , in CI, in order to achieve maximum usefulness, each class and its functions are highly autonomous.
CI is a dynamically instantiated, highly component-specific loosely coupled system
The above introduces the design and architectural goals of Codeigniter, including aspects of the content. I hope it will be helpful to friends who are interested in PHP tutorials.