Mongo has too many collection.

  mongodb, question

Just learning mongo, I don’t know how to deal with this requirement properly:

Each user has a prefix to create many collection names similar to this: user1_abcd
There are n users and n collection per user.
I would like to list that there is no single interface to implement all the collectionsmongo of a user, but to judge it by obtaining all the collection then traversing it, which seems to me to be very inefficient.

I would like to consult the experts to see if there is any more efficient way.

What is the appeal of establishing multiple collection for each user ..?

Why can’t usr1a usr1b usr1c usr2a usr2b usr2C this unlucky structure is changed to …

A b c three collection each store a copy of usr1 and usr2 data ..?