Configuring Dimension Information

A dimension is either a column on the fact model or a relation to another table. They are used to group information together for aggregates. For example, a report on orders dimensioned by sales agent would join the orders fact model to agents and yields data grouped by agent.

Declaring dimensions on a fact model

You must declare what a fact model is dimensional by. A valid dimension is a column on the fact model's ActiveRecord model or a belongs_to/has_one through relationship. has_many relationships do not work (well) at all.

class TicketFactModel < ActiveReporting::FactModel
  dimension :creator # belongs_to relationship
  dimension :assignee # belongs_to relationship
  dimension :category # Column on the tickets table
end

When a fact model is used as a dimension

When another fact model uses a relationship as a dimension, that ActiveRecord model's fact model class can hold configuration information for how to act when used as a dimension.

By default, it is assumed a dimension's label is a column called name. This can be changed on the fact model.

class UserFactModel < ActiveReporting::FactModel
  default_dimension_label :username
end