What is the return value of update_all() in ActiveRecord / Ruby on Rails?

Question

The Ruby on Rails and ActiveRecord documentation, Google, and StackOverflow are conspiratorially silent on the return value of update_all()

What does update_all() return?

• Number of records?
• Success status?
• ID's of updated records?

Answer 1

ActiveRecord's update_all() returns the number of records updated.

describe '.update_all' do
  let!(:user1) { create :user, last_name: 'Smitty' }
  let!(:user2) { create :user, last_name: 'Smitty' }
  let!(:user3) { create :user, last_name: 'Doe' }

  it 'returns number of records updated' do
    expect(User.where(last_name: 'Smitty')
               .update_all(last_name: 'Smith')).to eq 2
  end
end

Yields:

User
  .update_all
    returns number of records updated

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1 example, 0 failures

Answer 2

The documentation has been updated:

Returns the number of rows affected.

https://api.rubyonrails.org/v6.1.4/classes/ActiveRecord/Relation.html#method-i-update_all