AlterTable

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

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 and Sebastian Roebke

Please find out more about our work in our dev blog.

Copyright © 2010 XING AG

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