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Rails Migrations Cheatsheet

Up and down methods, rake tasks, column mapping, loading fixtures, example migration file, all packed onto one A4 page for an easy at-a-glance reference. Updated for Rails 2.1

Table Methods - migration methods for creating and updating tables
Database mapping - how migration column types map to your underlying database
Example migration - What a migration file looks like
Rake tasks - a list of built-in migration-related Rake tasks
Directory Structure - where migration files go
Shortcut methods - various convenience methods
Column Methods - methods that operate on database columns
Index methods - methods for creating indexes
Miscellaneous methods - other methods
script/generate - generate a template migration file
Loading fixtures - load fixtures into your database via a migration

View all on one page

Miscellaneous methods

execute

Takes a single string identifying a valid SQL command to execute directly.

    execute "alter table line_items add constraint fk_line_item_products foreign key (product_id) references products(id)"

IrreversibleMigration

Use in the down method of a migration file to raise an exception when the up methods of the same migration file can not be reversed, e.g. changing a column type from :integer to :string.

    raise ActiveRecord::IrreversibleMigration

New in Rails 2.0: Sexy Migrations

A look at the new features and syntax available in migrations on Rails 2.0 More

Auto migrations

A brilliant plugin that makes changing your database schema even easier and faster. More