What is the purpose of using mongodb?

Question

MongoDB

I had such a question on mongo, as I study it, I don’t fully understand for what tasks mongo is still needed. As I understand it, when creating a CRM system on mongo, it’s better to go from a bunch from one to many. For a messanger, mongo is most likely ideal for one user who has his own settings (personal data, etc.) and a lot of chat_Id and a separate chat_id base stores all correspondence, the application and a lot of things. But let's say in the CRM system the best option is to start from the relation right? or build everything differently. A customer base where all orders, tasks, deliveries, payments and more are stored in it. Or am I thinking wrong?
It's just not clear where you can use mongo

Answer 1

CRM - of course relational database. This will normalize the database and ensure data integrity at the database level.
MongoDB (including other NoSQL) - when there is no connection between data or it is insignificant. Logs - good, IMHO, an example for storage in NoSQL. You can do the same with chat.

Answer 2

the best option is to come from a relation right?

No, you need to look at features, on average, you can try Mongo if you don't need (complex) transactions.