Data Loading

includes — eager-load ActiveRecord associations to avoid N+1 queries:

includes [
  :customer,
  product: {
    category: [:category, :brand]
  },
]

prefetch — run arbitrary code after records are loaded to attach computed data that is not stored in the database:

prefetch do |records|
  OutstandingAmountService.instance.get_outstanding_amounts(records).each do |order_id, outstanding_amount|
    order = records.find { |r| r.id == order_id }
    order.outstanding_amount = outstanding_amount if order
  end
end

prefetch receives the full collection of records returned by the index query and runs after includes is applied. Use it to batch-load calculated values (debts, external API data, aggregated counts) so the frontend schema receives them without triggering per-record queries.

scopes — apply named ActiveRecord scopes to the base query before filtering:

scopes [:active, :visible]

Each scope name is called as .public_send(scope) on the relation. Scopes are applied after policy_scope and before filters.

default_filter — merge a fixed set of filter params into every index query:

default_filter({ status: 'active' })

force_sorting — when true, the default_sorting value cannot be overridden by the order_by query parameter:

force_sorting true

The parameter is then not read at all, so a request carrying one is served with the forced ordering rather than refused. What a client may put in order_by otherwise is on Filtering and Searching.