25 lines
502 B
Ruby
25 lines
502 B
Ruby
# frozen_string_literal: true
|
|
|
|
class AddUniqueIndexToDevelopers < ActiveRecord::Migration[6.0]
|
|
def up
|
|
execute <<~SQL
|
|
DELETE FROM developers d1
|
|
USING (
|
|
SELECT MAX(id) as id, user_id
|
|
FROM developers
|
|
GROUP BY user_id
|
|
HAVING COUNT(*) > 1
|
|
) d2
|
|
WHERE
|
|
d1.user_id = d2.user_id AND
|
|
d1.id <> d2.id
|
|
SQL
|
|
|
|
add_index :developers, %i[user_id], unique: true
|
|
end
|
|
|
|
def down
|
|
raise ActiveRecord::IrreversibleMigration
|
|
end
|
|
end
|