php - Getting started with 'No SQL' Cloud DB , Which one is better to learn??? -

I am currently working on Codeigniter-MySQL.

Now I want to learn some 'SQL' cloud database which is good for starting with one should be easy to use with my PHP, codeigniter projects.

You can not use regular active record classes In CI, the structure is completely different.

However, this is definitely the evidence that people are working in Code Igniter. There is a library.