When should I use a NoSQL database instead of a relational database? Is it okay to use both on the same site?

Question

What are the advantages of using NoSQL databases? I\'ve read a lot about them lately, but I\'m still unsure why I would want to implement one, and under what circumstances I

Answer 1

I designed and implemented solutions with NoSQL databases and here is my checkpoint list to make the decision to go with SQL or document-oriented NoSQL.

DON'Ts

SQL is not obsolete and remains a better tool in some cases. It's hard to justify use of a document-oriented NoSQL when

• Need OLAP/OLTP
• It's a small project / simple DB structure
• Need ad hoc queries
• Can't avoid immediate consistency
• Unclear requirements
• Lack of experienced developers

DOs

If you don't have those conditions or can mitigate them, then here are 2 reasons where you may benefit from NoSQL:

• Need to run at scale
• Convenience of development (better integration with your tech stack, no need in ORM, etc.)

More info

In my blog posts I explain the reasons in more details:

• 7 reasons NOT to NoSQL
• 2 reasons to NoSQL

Note: the above is applicable to document-oriented NoSQL only. There are other types of NoSQL, which require other considerations.