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16 lines
878 B
16 lines
878 B
class AddIndexToPollAnswer < ActiveRecord::Migration[5.2]
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def change
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remove_index :poll_votes, column: [:poll_question_id, :user_id]
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change_column_default :poll_votes, :poll_question_id, from: nil, to: -1
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PollVote.where(poll_answer_id: nil).update_all(poll_answer_id: -1)
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sql = %Q(delete from poll_votes where (poll_question_id, user_id, poll_answer_id) in
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(select * from (select poll_question_id, user_id, poll_answer_id from poll_votes group by poll_question_id, user_id, poll_answer_id having count(*) > 1) a)
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and id not in (select * from (select min(id) from poll_votes group by poll_question_id, user_id, poll_answer_id having count(*) > 1 order by id) b))
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ActiveRecord::Base.connection.execute sql
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add_index :poll_votes, [:poll_question_id, :user_id, :poll_answer_id], name: 'poll_answer_index', unique: true
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end
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end
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