So what's the best way to create new tables in a Sqlite database in Rails 2. I have created the database using rake db:migrate command. So should I write individual sql scripts to create a database or use rake somehow. I don't need scaffolding.
asked Oct 14, 2008 at 6:29
Malik Daud Ahmad Khokhar
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3 Answers
Basically use migrations.
Some useful help on how to use migrations is available at http://wiki.rubyonrails.org/rails/pages/understandingmigrations and http://wiki.rubyonrails.org/rails/pages/UsingMigrations. A good cheatsheet that I use is also available at http://dizzy.co.uk/ruby_on_rails/cheatsheets/rails-migrations.
Basically migrations use ruby code to create your database tables for you. It is far easier (in my opinion at least) to use nice ruby code to do this rather than SQL DDL - it also does various things automatically for you (like adding id fields to all your tables as rails requires). You can then use rake tasks to actually apply the migrations to your database. The other major advantage that migrations give you is that they are reverseable - so your database is versioned and you can easily jump from one version to another.
2 Comments
domgblackwell
Another source is the Rails guide at guides.rails.info/migrations/migrations.html
Justin Tanner
All the links except for the (cheatsheet) are dead.
Try to avoid writing CREATE/ALTER table scripts and use ActiveRecord migrations instead. A few reasons spring to mind:
- Portability: it's much easier to let AR deal with cross-platform flavour differences
- Change control: your migrations can manage changes in both directions with the VERSION= option, something that's not easy to do with SQL
- It's the Rails way: follow the Rails conventions unless you have a compelling reason not to do so
- Simplicity: you don't have to worry about id and timestamp columns when you use migrations, which saves you having to remember them if you work in SQL
Comments
If you are not using scaffolding then you should use script/generate migration to create a migration file for each table. There is no need to use sql scripts. After creating some migrations you can apply them to your database using rake db:migrate.
