sequel-annotate¶ ↑

sequel-annotate annotates Sequel models with schema information. By default, it includes information on columns, indexes, and foreign key constraints for the current table.

On PostgreSQL, this includes more advanced information, including check constraints, triggers, comments, and foreign keys constraints for other tables that reference the current table.

The schema comments are kept at the end of the file by default, using a format similar to:

class Item < Sequel::Model
end

# Table: items
# Columns:
#  id                    | integer               | PRIMARY KEY DEFAULT nextval('items_id_seq'::regclass)
#  category_id           | integer               | NOT NULL
#  manufacturer_name     | character varying(50) |
#  manufacturer_location | text                  |
#  in_stock              | boolean               | DEFAULT false
#  name                  | text                  | DEFAULT 'John'::text
#  price                 | double precision      | DEFAULT 0
# Indexes:
#  items_pkey        | PRIMARY KEY btree (id)
#  name              | UNIQUE btree (manufacturer_name, manufacturer_location)
#  manufacturer_name | btree (manufacturer_name)
# Check constraints:
#  pos_id | (id > 0)
# Foreign key constraints:
#  items_category_id_fkey       | (category_id) REFERENCES categories(id)
#  items_manufacturer_name_fkey | (manufacturer_name, manufacturer_location) REFERENCES manufacturers(name, location)
# Triggers:
#  valid_price | BEFORE INSERT OR UPDATE ON items FOR EACH ROW EXECUTE PROCEDURE valid_price()

gem install sequel-annotate

After loading the models:

require 'sequel/annotate'
Sequel::Annotate.annotate(Dir['models/*.rb'])

That will append or replace the schema comment in each of the files. It’s best to run this when the repository is clean, and then use your source control tools (e.g. git diff) to see the changes it makes.

In some cases, sequel-annotate may not be able to correctly guess the model for the file. In that case, you may need to create an instance manually:

sa = Sequel::Annotate.new(Item)
sa.annotate('models/item.rb')

If you want to get the schema comment for a model without appending it to a file:

sa.schema_comment

If you want to put the schema comment at the beginning of the file you can use the :position option:

Sequel::Annotate.annotate(Dir['models/*.rb'], position: :before)

or

sa = Sequel::Annotate.new(Item)
sa.annotate('models/item.rb', position: :before)

If your models are nested in a namespace:

module ModelNamespace
  class Item < Sequel::Model
  end
end

Then you can use the :namespace option to set the namespace to use:

Sequel::Annotate.annotate(Dir['models/*.rb'], namespace: 'ModelNamespace')

For PostgreSQL, you can optionally leave out indexes, foreign_keys, references, triggers, comments, and constraints by passing in false as a parameter as follows:

Sequel::Annotate.annotate(Dir['models/*.rb'], foreign_keys: false,
                          :indexes: false, constraints: false, comments: false)

The columns section can have a border on the top and bottom for easier visual distinction by setting the :border option to true

Sequel::Annotate.annotate(Dir['models/*.rb'], border: true)

Models that use datasets that select from subqueries are automatically skipped, as annotations don’t really make sense for them since they are not backed by a table. You can skip other models by using a # sequel-annotate: false magic comment somewhere in the file.

Here’s an example rake task for sequel-annotate:

desc "Update model annotations"
task :annotate do
  # Load the models first
  Dir['models/*.rb'].each{|f| require_relative f}

  require 'sequel/annotate'
  Sequel::Annotate.annotate(Dir['models/*.rb'])
end

Tests of sequel-annotate itself can be run with rake:

rake

Set the SEQUEL_ANNOTATE_SPEC_POSTGRES_URL environment variable or appropriate libpq environment variables to specify which PostgreSQL database to connect to.

MIT

Jeremy Evans <code@jeremyevans.net>

Based on [annotate-sequel]{github.com/kennym/annotate-sequel} by Kenny Meyer.