gitlab-org--gitlab-foss/db/migrate/20160725104020_merge_request_diff_remove_uniq.rb
Jan Provaznik 0fc9f9d3e7 Add version 4.2 to all existing migrations
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
2018-11-22 13:18:28 +01:00

36 lines
1.1 KiB
Ruby

# See http://doc.gitlab.com/ce/development/migration_style_guide.html
# for more information on how to write migrations for GitLab.
# rubocop:disable RemoveIndex
class MergeRequestDiffRemoveUniq < ActiveRecord::Migration[4.2]
include Gitlab::Database::MigrationHelpers
disable_ddl_transaction!
DOWNTIME = false
def up
constraint_name = 'merge_request_diffs_merge_request_id_key'
transaction do
if index_exists?(:merge_request_diffs, :merge_request_id)
remove_index(:merge_request_diffs, :merge_request_id)
end
# In some bizarre cases PostgreSQL might have a separate unique constraint
# that we'll need to drop.
if constraint_exists?(constraint_name) && Gitlab::Database.postgresql?
execute("ALTER TABLE merge_request_diffs DROP CONSTRAINT IF EXISTS #{constraint_name};")
end
end
end
def down
unless index_exists?(:merge_request_diffs, :merge_request_id)
add_concurrent_index(:merge_request_diffs, :merge_request_id, unique: true)
end
end
def constraint_exists?(name)
indexes(:merge_request_diffs).map(&:name).include?(name)
end
end