I'm planning to build a wiki/resource app which, by itself, makes sense to be using Mongo for. However, the primary purpose of the app is to have associative tables showing connections between individual content items. A majorly simplified example would be, Odin, Zeus, Jupiter would be a row within an "Allfather" association. The problem is that these tables could grow indefinitely and it seems like developing this type of network in Mongo would be a rather complex and frustating experience.
I've thinking about using Mongo for the pages and just maintaining a small Postgres database for these associations, but something intuitively feels wrong about that. However, I'm an experienced frontend dev that's just starting to dabble in backend/database, so I'm not willing to trust my intuitions on databases yet haha.
Is postgres + mongo a good solution for the above problem, or is this where something like a graph database (which I only learned about yesterday) would come into play?
After spending the last several hours researching further, it does appear that a graph database is the right solution to managing the "association" feature that I'm looking to develop here because the actual relationships will be rather multidimensional in nature.
Furthermore, I've decided to go with ArangoDB as it merges key-value (ie. Redis or postgres' hstore IIRC), document store (ie. Mongo's documents or Postgres' JSONB), and also does graph database functionality. Arango can do joins between documents and, even better, it has a single, unified query language that works across all 3 types of models. It also has a rather robust tooling environment around it already that seems pretty promsing.
I found this youtube video rather enlightening as well if anyone wants a nice introduction to understanding why you might want to use a "multi-model database" like ArangoDB.