scenic-cascade
scenic-cascade
is a scenic migration file generator that supports cascading view updates.
Installation
Add this line to your application's Gemfile:
gem 'scenic-cascade'
And then execute:
$ bundle install
Or install it yourself as:
$ gem install scenic-cascade
Usage
To generate migration files, use scenic:view:cascade
generator instead of scenic:view
.
The following example generates migration files for search_results
view.
$ bin/rails generate scenic:view:cascade search_results
create db/views/search_results_v01.sql
create db/migrate/20220714233704_create_search_results.rb
How it works
Consider a situation where the following three views exist:
first_results
is a parent view (version 1)second_results
is a materialized view that depends onfirst_results
(version 3)third_results
is a view that depends onfirst_results
andsecond_results
(version 2)
-- first_results
SELECT 'foo' AS bar;
-- second_results
SELECT * FROM first_results;
-- third_results
SELECT * FROM first_results UNION SELECT * FROM second_results;
Executing the scenic:view:cascade
generator for first_results
in this state will generate the following migration file:
$ bin/rails generate scenic:view:cascade first_results
create db/views/first_results_v02.sql
create db/migrate/20220714233704_update_first_results_to_version_2.rb
Since all dependencies are described, you can execute bin/rails db:migrate
without changing the migration file.
[!WARNING] Currently, index re-creation is not supported. Please change a migration file to recreate indexes if it contains
drop_view
for materialized views.
class UpdateSearchResultsToVersion2 < ActiveRecord::Migration
def change
drop_view :third_results, revert_to_version: 2, materialized: false
drop_view :second_results, revert_to_version: 3, materialized: true
replace_view :first_results, version: 2, revert_to_version: 1
create_view :second_results, version: 3, materialized: true
create_view :third_results, version: 2, materialized: false
end
end
Development
After checking out the repo, run bin/setup
to install dependencies. Then, run rake spec
to run the tests. You can also run bin/console
for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install
. To release a new version, update the version number in version.rb
, and then run bundle exec rake release
, which will create a git tag for the version, push git commits and the created tag, and push the .gem
file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/akiomik/scenic-cascade. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.
Code of Conduct
Everyone interacting in the `scenic-cascade' project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.