What is the difference between library and model in CodeIgniter Framework?

Question

I am new to CI. Before I had worked extensively in RoR and Symfony.

I am unable to understand why exactly CI provides Library and Models. Most of the CI code I examined

Answer 1

The basci thought on Libraries was a way to extend Codeigniter's functionality through classes.

If you compare the blank anatomy of a Library and a Model in Codeigniter, you will see that Models extend the CI_MODEL which allows you to access Codeigniter's native resources (for Example $this->db).

Libraries do not offer that basic access and they also do not need to be extended through the CI_MODEL.

Models are made to depict and interact with data (mostly abstracted from databases such as mysql).

Take a look at the basic Library

...and the Model anatomy

In most cases the Models are prepared to use Ressources to access databases or other functionalities. Libraries don't. You need to include or extend the Ressources manually if you need them:

//Create an CI instance
$CI =& get_instance();

Libraries are tool collections and function extensions while Models are natively ideal for abstracting and interacting with data coming from databases.