0fc9f9d3e7
DB schema generated by a migration may look different in rails 4 and 5 (because rails 5 may use different default values). For this reason it's important to explicitly set for which rails version a migration was written for. See https://stackoverflow.com/questions/35929869/activerecordmigration-deprecation-warning-asks-for-rails-version-but-im-no/35930912#35930912
32 lines
853 B
Ruby
32 lines
853 B
Ruby
class RemoveDuplicatedNotificationSettings < ActiveRecord::Migration[4.2]
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def up
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duplicates = exec_query(%Q{
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SELECT user_id, source_type, source_id
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FROM notification_settings
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GROUP BY user_id, source_type, source_id
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HAVING COUNT(*) > 1
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})
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duplicates.each do |row|
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uid = row['user_id']
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stype = connection.quote(row['source_type'])
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sid = row['source_id']
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execute(%Q{
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DELETE FROM notification_settings
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WHERE user_id = #{uid}
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AND source_type = #{stype}
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AND source_id = #{sid}
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AND id != (
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SELECT id FROM (
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SELECT min(id) AS id
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FROM notification_settings
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WHERE user_id = #{uid}
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AND source_type = #{stype}
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AND source_id = #{sid}
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) min_ids
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)
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})
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end
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end
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end
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