What is NoSQL?

Our team moving to NoSQL DB for my current project.(I've only used SOL originally...) So I'm going to think about it. Actually we plan to firebase.

My questions are ...
① What's good about NoSQL?
② What's bad about NoSQL?
③ I mean...actually what does SQL mean?
④ How do we design NoSQL DB...what is best practice?

① What's good about NoSQL?

• Fast processing!
• Easier!! to handle scale-out

② What's bad about NoSQL?

• Data integrity is difficult to maintain
• Data processing is difficult

③ I mean...actually what does SQL mean?

• A database language for manipulating and defining data. ex...SELECT,INSERT,UPDATE,DELETE

④ How do we design NoSQL DB...what is best practice?

• I don't know yet......................

Reference site
■Client Side Join
https://qiita.com/1amageek/items/afc1c0ceb15ffc2372fd
■What is RESTful API
https://qiita.com/NagaokaKenichi/items/0647c30ef596cedf4bf2#restful-api%E3%81%A8%E3%81%AF