Hi all,
I'm working on a large rails projects that has a lot of migration files (around 80). Through some development quirk, probably due to bad svn merging, my local database hasn't run migration 63. Is there a way to run this one file without having to roll back through all the later migrations, which would cause significant data loss?
Many thanks, Adam
% rake db:migration:up VERSION=63
Christian
Hi Christian,
That rake task didn't work for me. However, I googled "db:migrate:up" and found the task as part of the easily_migrate plugin. This was still not what I'm looking for - db:migrate:up just moves the db up one version, it cannot pick out an arbitrary migration to run. I added a few of my own tasks to achieve what I wanted - the code is pasted below if anyone needs it.
Basically I've written three tasks in addition to those from easily_migrate (Google Code Archive - Long-term storage for Google Code Project Hosting.):
db:specific:up VERSION=X Sets the database to version X-1, migrates to version X, resets to the current version
db:specific:down VERSION=X Sets the database to version X, migrates to version X-1, resets to the current version
db:specific:redo VERSION=X Sets the database to version X, migrates to version X-1, migrates back to version X, resets to the current version
I think these could be quite handy especially if you want to refactor your old migrations or if you've missed out a column somewhere and don't want to have to write a whole new migration for it. I hope it's helpful to someone!
namespace :db do namespace :version do desc "Manually set the schema version to an arbitrary number, used to recover from failed migration states. VERSION to be given" task :set => :environment do # eval "#{model_or_raise}.to_fixture(#{limit_or_nil_string})" if ENV['VERSION'].blank? raise "No version supplied Current Version: #{ActiveRecord::Migrator.current_version}. Set VERSION to change version." else puts "Current Version: #{ActiveRecord::Migrator.current_version}\r\n" ActiveRecord::Migrator.set_schema_version(ENV['VERSION']) puts "New version: #{ActiveRecord::Migrator.current_version}" end end end
namespace :migrate do desc "Like db:migrate except it automatically targets the next version up" task :up => :environment do ActiveRecord::Migrator.migrate("db/ migrate/",ActiveRecord::Migrator.current_version.to_i + 1 ) puts "New version: #{ActiveRecord::Migrator.current_version}" end
desc "Like db:migrate except it automatically targets the next version down" task :down => :environment do ActiveRecord::Migrator.migrate("db/ migrate/",ActiveRecord::Migrator.current_version.to_i - 1 ) unless ActiveRecord::Migrator.current_version == 0 puts "New version: #{ActiveRecord::Migrator.current_version}" end
namespace :specific do desc "Run a specific migration - sets the DB to the version below and migrates once" task :up => :environment do if ENV['VERSION'].blank? raise "No version supplied Current Version: #{ActiveRecord::Migrator.current_version}. Set VERSION to change version." else current_version = ActiveRecord::Migrator.current_version puts "Current Version: #{current_version}\r\n"
ActiveRecord::Migrator.set_schema_version(ENV['VERSION'].to_i - 1) puts "Set to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.migrate("db/ migrate/",ActiveRecord::Migrator.current_version.to_i + 1 ) puts "Migrated to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.set_schema_version(current_version) puts "Reset to version: #{ActiveRecord::Migrator.current_version}" end end
desc "Run a specific migration - sets the DB to the version below and migrates once" task :down => :environment do if ENV['VERSION'].blank? raise "No version supplied Current Version: #{ActiveRecord::Migrator.current_version}. Set VERSION to change version." else current_version = ActiveRecord::Migrator.current_version puts "Current Version: #{current_version}\r\n"
ActiveRecord::Migrator.set_schema_version(ENV['VERSION'].to_i) puts "Set to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.migrate("db/ migrate/",ActiveRecord::Migrator.current_version.to_i - 1 ) puts "Migrated to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.set_schema_version(current_version) puts "Reset to version: #{ActiveRecord::Migrator.current_version}" end end
desc "Redo a specific migration: run it's down method then it's up method" task :redo => :environment do if ENV['VERSION'].blank? raise "No version supplied Current Version: #{ActiveRecord::Migrator.current_version}. Set VERSION to change version." else current_version = ActiveRecord::Migrator.current_version puts "Current Version: #{current_version}\r\n"
ActiveRecord::Migrator.set_schema_version(ENV['VERSION'].to_i) puts "Set to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.migrate("db/ migrate/",ActiveRecord::Migrator.current_version.to_i - 1 ) puts "Migrated to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.migrate("db/ migrate/",ActiveRecord::Migrator.current_version.to_i + 1) puts "Migrated to version: #{ActiveRecord::Migrator.current_version}" ActiveRecord::Migrator.set_schema_version(current_version) puts "Reset to version: #{ActiveRecord::Migrator.current_version}" end end end end end
script/console
require 'db/migrate/20090418023701_add_product_messages.rb'
=> ["AddProductMessages"]
AddProductMessages.up
== AddProductMessages: migrating