20 lines
717 B
Ruby
20 lines
717 B
Ruby
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# ref: https://dev.to/nodefiend/rails-migration-adding-a-unique-index-and-deleting-duplicates-5cde
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class AddUniqueIndexOnInboxMembers < ActiveRecord::Migration[6.1]
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def up
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# partioning the duplicate records and then removing where more than one row is found
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ActiveRecord::Base.connection.execute('
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DELETE FROM inbox_members WHERE id IN (SELECT id from (
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SELECT id, user_id, inbox_id, ROW_NUMBER() OVER w AS rnum FROM inbox_members WINDOW w AS (
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PARTITION BY inbox_id, user_id ORDER BY id
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)
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) t WHERE t.rnum > 1)
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')
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add_index :inbox_members, [:inbox_id, :user_id], unique: true
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end
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def down
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remove_index :inbox_members, [:inbox_id, :user_id]
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end
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end
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