Time to learn Cassandra/ MongoDB [closed]

Question

I am going to start learning NOSQL databases (in practices, already done my researches and understood the concepts and modeling approaches). I am working with time series data and both cassandra and mongodb are recommended for this use case. I would like to know which one takes less time to learn? (Unfortunately, I don't have much time to spend on learning) PS: I noticed that there are more tutorials and documentations with mongoDB (am I correct?) Thank you!

Answer 1

Having used them both extensively, I can say that the learning curve isn't as bad as you might think. But as different people learn and absorb information at different rates, it is difficult to say which you will find easier or how quickly you will pick them up. I will mention that MongoDB has a reputation of being very developer-friendly, due to the fact that you can write code and store data without having to define a schema.

Cassandra has a little steeper learning curve (IMO). However that has been lessened due to the CQL table-based column families in recent versions, which help to bridge the understanding gap between Cassandra and a relational database. Since tutorials for MongoDB have been mentioned, I will post a link to DataStax's Academy, which offers a free online course you can take to introduce yourself to Cassandra. Specifically, the course DS220 deals with modeling your data.

With both, a key concept to understand is that you must break yourself of the relational database idea where you want to build your tables/collections to store your data most-efficiently. In non-relational data modeling you will want to model your tables/collections to reflect how you want to query your data, and this might mean using redundant data in some places.