29 lines
555 B
Ruby
29 lines
555 B
Ruby
class MakePostNumberDistinct < ActiveRecord::Migration[4.2]
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def up
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DB.exec('update posts p
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set post_number = calc
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from
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(
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select
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id,
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post_number,
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topic_id,
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row_number() over (partition by topic_id order by post_number, created_at) calc
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from posts
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where topic_id in (
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select topic_id from posts
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group by topic_id, post_number
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having count(*)>1
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)
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) as X
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where calc <> p.post_number and X.id = p.id')
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end
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def down
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# don't want to mess with the index ... its annoying
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raise ActiveRecord::IrreversibleMigration
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end
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end
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