Changeset » Associations
Changesets can be associated with each other using Changeset#associate method, which will automatically set foreign keys for you, based on schema associations. Let's define :users relation that has many :tasks:
class Users < ROM::Relation[:sql]
schema(infer: true) do
associations do
has_many :tasks
end
end
end
class Tasks < ROM::Relation[:sql]
schema(infer: true) do
associations do
belongs_to :user
end
end
end
With associations established in the schema, we can easily associate data using changesets and commit them in a transaction:
task = tasks.transaction do
user = users.changeset(:create, name: 'Jane').commit
new_task = tasks.changeset(:create, title: 'Task One').associate(user)
new_task.commit
end
task
# {:id=>1, :user_id=>1, :title=>"Task One"}