What is the best way to structure this model/DB assiociations

Question

I am creating a project, and I want to structure the databases in the best way possible. I have a model called Event, now i would like a single event (think a baseball game) to belong to a month (ie August) and belong to a category (ie baseball) AND belong to a user (ie current_user)

In otherwords, I would like a month, a category, and a user to have many events, but I don't want the events to be duplicated. The same event object would be returned by:

august.events.find_by_id(1)
baseball.events.find_by_id(1)
current_user.events.find_by_id(1)

Any tips? My initial thought is to just set up the relations as I described above.. But I am curious to what is the best approach to creating an event object since:

august.events.new("foo")
baseball.events.new("foo")
current_user.events.new("foo")

would all yield three different event objects, when I am looking to just create one.

Can I do something like this?

Event.new(:category => "baseball", :month => "august")

then what would be the best approach to declaring a user "has that" event, and from there run commands such as baseball.events.all and august.events.all. And how would I dive deeper into the association madness if I wanted say Category -> Sports -> Baseball -> event

Thanks for any help, it is much appreciated.

Answer 1

this isn't an answer, per se. It is mainly to give you an idea of the flexibility of the API.

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The schema, from what I can tell, is correct. Event has month and category (or category_id ) and user_id . You can create all manner of helper methods to operate on that model.

For example, with a few scopes:

class Event
  scope :for_month,    ->(m) { where(month: m) }
  scope :for_category, ->(c) { where(category: c) }
  scope :for_user,     ->(u) { where(user: u) }
end

# usage

Event.for_month("august").for_category("baseball").for_user(current_user)

# below, month "august" will be set on instance
current_user.events.for_month("august").new("foo") 

But all of this is pointless. With those relationships in place, you can access the Event from User or Category and fill in the details yourself:

Event.where(month: "august", category: "baseball", user: current_user)
current_user.events.where(month: "august", category: "baseball")

current_user.events.new(month: "august", category: "baseball")

There are a tonne of ways to access and manipulate this data. I'm not sure you can reduce it much further than the above. You could go crazy and add a scope with multiple arguments:

class Event
  scope :for_mcu, ->(m, c, u) {
    for_month(m).for_category(c).for_user(u)
  }
end

# usage

Event.for_mcu("august", "baseball", current_user)