MongoDB relationships: embed or reference?

Question

I'm new to MongoDB--coming from a relational database background. I want to design a question structure with some comments, but I don't know which relationship to use for comments: embed or reference?

Do I have to use ref not embed? Then I have to create a new collection for comments?

Answer 1

Embed is good if you have one-to-one or one-to-many relationships between entities, and reference is good if you have many-to-many relationships.

Answer 2

While dealing with unstructured data, in MongoDB, embedding may be better for all the instances where there is a strong correlation between the data. If something feels strange while shaping the data with embedding (such as relationships that result in data duplication under multiple top-level objects), you can switch to referencing. Referencing should be used more delicately as there are restrictions to referenced documents and references are less effective as compared to the embedded.