Single step batch delete in Ruby on Rails

Question

How to send such a query to database server from Rake task without removing record-by-record in "each" loop?

delete from data
where uuid in (
    select uuid
    from data
    group by uuid, raw, recdate
    having count(*)>1
);

Blotto

Answer 1

ActiveRecord has the delete_all method for you. Note that it does not call the destroy callbacks. http://api.rubyonrails.org/classes/ActiveRecord/Relation.html#method-i-delete_all

Quagga

Is there a rails console function which calls destroy callbacks when deleting parents? – Bedsore

.destroy_all does it but that is not a single-step batch delete the question asked for. – Quagga

Answer 2

For me, I use small query to iterate over deletes

while Topic.limit(1000).delete_all > 0 do
  next
end

Redhot

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