Recommendations on structure for Mongoid/MongoDB Tree of Tags

Question

I\'m looking for some recommendations on how to structure the tags part of this data model:

Here\'s a simplified version of it:

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Answer 1

there are two implemented patterns of mongodb tree structure

Answer 2

Do you need to update the structure of the tree (i.e. move a tag to another parent)? If that is possible, the embedded approach would become difficult, and the relational/normalized approach makes more sense.

I would probably store the tags themselves in the document (embedded), but if there is any chance that I need to move tree nodes around on-line, then I'd store the hierarchy in another document. Queries need not be slow, if you first flatten the search query (according to the current tree) and then search for those tags. This approach probably does not scale to well if the flattened search query ends up having hundreds of tags in them (how tall is your tree?).

If tags cannot be moved to new parents (or only by you, during scheduled maintenance), go ahead and embed the whole hierarchy.