ActiveRecord Update_all to variable value

Question

I'm looking for a way to update all record with certain condition their cur_val + 100:

I have a table Suggestions with id and score fields, and I want all the entries with specific ids to receive a score bump, e.g:

Suggestion.where(id: ids_list).update_all(score: score+100)

How do I do that?

Answer 1

Try plain SQL, read about update_all:

Suggestion.where(id: ids_list).update_all('score = score + 100')

But remember update_all not trigger Active Record callbacks or validations.

Some tips:

You can do it in Ruby but this very bad:

Suggestion.where(id: ids_list).find_each do |x|
  x.update(score: x.score + 100)
end

Things like this should happen in database.