How to store short term data?

Question

Node.js

I started actively practicing node and this is a very good thing.
I use a package to work with mysql, but one proger friend said that I was an idiot. I had to joke around.
When writing the application, I stored everything in one array variable (var) and added additional arrays to it (group data is acceptable). But it's all stored in RAM, I think.
I read about many DBMS under node, but I can’t figure out what will fit in the end.

Answer 1

The use of SQL, NoSQL and in-memory variables is very case specific!!!
SQL is used if you need SQL-style data selections - for example, tricky Joins from several pages.
NoSQL is used for online storage of some data. For example, you have some active simple table operations, but there are a lot of them.
Memory is basically the same as NoSQL. The only difference is that you have one application in memory -> one memory area. SQL and NoSQL can serve multiple server instances (multiple servers).
Idiocy - to take NoSQL, and then start writing SQL functionality into it on the node, which is often what people are perverted.

Answer 2

radish / tarantula / aerospike / other storage in memory suitable for the task
problem with storage in the process memory - this solution is not scalable, it is worth running the 2nd process of the node, and that's it, you will have data out of sync