Use 2 collections (tables). Users - id - events_attended (array of event ids) Events - id - users_attended (array of user ids) If you want to get events

Use 2 collections (tables). Users - id - events_attended (array of event ids) Events - id - users_attended (array of user ids) If you want to get events a user attended, do a query like: 1) get the user.events_attended array 2) events.find({_id:{$in: [user.events_attended] }}) 3) now you have a nice json object of all events the user has been to If you want to get all users that went to an event: 1) get the event.users_attended array 2) users.find({_id:{$in: [event.users_attended] }}); 3) now you have a nice json object of all users who attended and event