ULID::Rails

This gem makes it possible to use ULID for DB primary keys in a Ruby on Rails app.

Installation

gem 'ulid-rails'

And then execute:

$ bundle

Or install it yourself as:

$ gem install ulid-rails

Usage

Migrations

If you use MySQL, specify id: false to create_table and add id column as 16-byte binary type.

  def change
    create_table :users, id: false do |t|
      t.binary :id, limit: 16, primary_key: true # MySQL
      # ...
    end
  end

If you use PostgreSQL, just specify id: :uuid to create_table

  def change
    create_table :users, id: :uuid do |t|
      # ...
    end
  end

Model Changes

Just add the below lines to your models.

class MyModel < ApplicationRecord
  include ULID::Rails
  ulid :id # The argument is the primary key column name
end

`created_at` virtual column

MySQL Only (for now)

Since ULID includes milli seconds precision timestamp, you don't need to store created_at. You can instead create a virtual column that extracts the timestamp from the ULID column.

Defining the virtual created_at is kind of comlicated so this gem provides a helper method for it.

    create_table :users, id: false do |t|
      t.binary :id, limit: 16, primary_key: true
      t.datetime :updated_at
      t.virtual_ulid_timestamp :created_at, :id
    end

virtual_ulid_timestamp takes two arguments, the first one is the name of the column name (typically, created_at) and the second one is the ULID column that creation timestamp is extracted from.

FAQ

Foreign Keys

You need to specicfy type option

    # MySQL
    create_table :admin_usees do |t|
      t.references :admin_user, foreign_key: true, type: "BINARY(16)"
    end

License

The gem is available as open source under the terms of the MIT License.

suratpyari/ulid-rails