An ActiveRecord object lifecycle: 1.new record item = Item.new item.new_record? #=> true 2.persisted item.save item.persisted? #=> true 3.changed item.name = “other” item.changed? #=> true 4.destroyed item.destroy item.destroyed? #=> true
Figured it out, the task should look like: namespace :test do task :new_task => :environment do puts Parent.all.inspect end end Notice the => :environment dependency added to the task
Model.select(:rating) The result of this is a collection of Model objects. Not plain ratings. And from uniq‘s point of view, they are completely different. You can use this: Model.select(:rating).map(&:rating).uniq or this (most efficient): Model.uniq.pluck(:rating) Rails 5+ Model.distinct.pluck(:rating) Update Apparently, as of rails 5.0.0.1, it works only on “top level” queries, like above. Doesn’t work on … Read more
There is a now a “correct” mechanism in Rails 4: >> Model.none => #<ActiveRecord::Relation []>
remove_column :table_name, :column_name For instance: remove_column :users, :hobby would remove the hobby Column from the users table.