Jim Lindley Notes

Rake db:reset Changes, schema.rb Info

November 10th, 2007

DHH has updated the docs for schema.rb, to reflect the fact that schema.rb is an important file that should be kept into version control. He recommends that production apps be initialized to their schema via this file, and not from migrations.

The rake db:reset task has been changed to reflect this philosophy, it will now run the db:schema:load instead of db:migrate after first dropping then recreating your database.

Migrations, as they build up over time, become increasingly fragile, whereas schema.rb is likely consistent to the current version of your schema and many fewer steps to load. One thing to keep in mind is that schema.rb does not preserve all the same setting that migrations do - character sets, collations, and other database dependent features. If you need those, switch from having a ruby schema.rb to an SQL schema file.

Switch to SQL by uncommenting this line in environment.rb:

# config.active_record.schema_format = :sql
Posted by Jim Lindley Filed in Edge Rails Notes, Rails

    Comments

  1. Nathan:

    I have used migrations in the past to load in initial data. Is this considered not proper in rails 2.0?

    The shema.rb fie wouldn’t work, I suppose I gotta start making my own rake tasks.

    November 11th, 2007 at 09:53 PM

  2. Jim Lindley:

    I use rake tasks – but they are not as quick or convenient in the short term as migrations are.

    November 11th, 2007 at 10:48 PM

  3. Joel AZEMAR:

    like Nathan i use the migration for load my fixture in development environement. In fact, every migration as one fixture associate like that :

    require ‘active_record/fixtures’

    class CreateRoles < ActiveRecord::Migration

    def self.up
    create_table :roles, :force => true do |t| t.string :title, :name t.timestamps end Fixtures.create_fixtures(File.join(File.dirname(FILE), “data”), “roles”) end

    def self.down drop_table :roles end

    end

    with the newest approch my fixture doesn’t loaded :(

    November 12th, 2007 at 06:23 AM

  4. Jim Lindley:

    Joel, you can create a custom rake task that replaces rake db:reset. Call it rake db:remigrate or the like.

    desc 'Drops database, recreates it, and re-runs migrations.' 
task :remigrate =&gt; ['db:drop', 'db:create', 'db:migrate']

    There’s a free screen cast on creating custom rake tasks if you’ve never done it before: Rails Cast, Rake Tasks

    November 12th, 2007 at 11:15 AM

  5. Joel AZEMAR:

    thanks a lot, i will be can replace my bash script :D

    November 13th, 2007 at 07:04 AM

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