Database suggestion (and possible readings) for heavy computational website

Question

I'm building a website that will rely on heavy computations to make guess and suggestion on objects of objects (considering the user preferences and those of users with similar profiles). Right now I'm using MongoDB for my projects, but I suppose that I'll have to go back to SQL for this one.

Unfortunately my knowledge on the subject is high school level. I know that there are a lot of relational databases, and was wondering about what could have been some of the most appropriate for this kind of heavily dynamic cluster analysis. Also I would really appreciate some suggestion regarding possible readings (would be really nice if free and online, but I won't mind reading a book. Just maybe not a 1k pages one if possible).

Thanks for your help, extremely appreciated.

Answer 1

Recommondations are typically a graph like problem, so you should also consider looking into graph databases, e.g. Neo4j