A rails plugin to execute multiple ADD, ALTER, DROP, and CHANGE clauses in a single ALTER TABLE statement.

http://github.com/xing/alter_table

This plugin lets you use an alter_table method in your ActiveRecord migrations to execute multiple ADD, ALTER, DROP, and CHANGE clauses in a single ALTER TABLE statement. Currently only supported for MySQL.

The benefits:

• Faster migrations - only one statement per altered table
• Simpler DSL for declaring alter table statements - almost an exact copy of ActiveRecord create_table syntax
• Support for more databases like PostgreSQL is planned

Prerequisites

• ActiveRecord

The plugin has been tested with ActiveRecord 2.3.5 and MySQL 5.0, but other versions are likely to work.

Installation

  cd path/to/your/rails-project
  ./script/plugin install git://github.com/xing/alter_table.git

Usage

  class AlterPeopleTable < ActiveRecord::Migration
    def self.up
      alter_table :people do |t|
        t.change_column(:first_name, :string, :default => "John", :null => false)
        t.add_column(:last_name, :string, :default => "Doe", :null => false)
        t.remove_column(:street)
        t.rename_column(:phone, :telephone)
        t.add_index(:last_name)
        t.remove_index(:zip)
      end
    end

    def self.down
      ...
    end
  end

The produced SQL would look like this:

  ALTER TABLE `people`
  CHANGE `first_name` `first_name` varchar(255) DEFAULT 'John' NOT NULL,
  ADD `last_name` varchar(255) DEFAULT 'Doe' NOT NULL,
  DROP `street`,
  CHANGE `phone` `telephone` varchar(64),
  ADD INDEX `index_people_on_last_name` (`last_name`),
  DROP INDEX `index_people_on_zip`

alter_table works almost like create_table. The following methods are available:

• change_column
• add_column
• remove_column
• rename_column
• add_index
• remove_index

All methods take the same parameters as the normal migration methods. Except, you always omit the table name as the first parameter.

Running the plugin tests

1. Modify test/database.yml to fit your test environment.
2. If needed, create the test database you configured in test/database.yml.

Then you can run

  rake test:plugins PLUGIN=alter_table

from your Rails project root or

  rake

from vendor/plugins/alter_table.

Authors

{Tim Payton}[http://github.com/dizzy42] and {Sebastian Roebke}[http://github.com/boosty]

Please find out more about our work in our {dev blog}[http://devblog.xing.com].

Copyright © 2010 {XING AG}[http://www.xing.com/]

Released under the MIT license. For full details see MIT-LICENSE included in this distribution.