Is it possible to output the SQL change scripts that 'rake db:migrate' produces?
5 Answers
Building on @qarol but even cooler, add this Rake task to one of your Rake files:
task :log => :environment do
ActiveRecord::Base.logger = Logger.new(STDOUT)
end
Then you can call ANY Rake task and have the output logged:
rake log db:migrate
4 Comments
Josh
You can use this: ActionMailer::Base.logger = ActiveRecord::Base.logger = Logger.new(STDOUT) to get mailer output as well.
Alan LaMielle
This worked great and is much more generic. It should be the accepted answer.
Jeremy Moritz
Put this script in a new file called
log_migration.rake (or whatever) and drop it in the lib/tasks directory
Mikey T.K.
This
ActiveRecord::Base.logger... statement can also be placed in the default Rakefile to unconditionally output all migration statements.You can create a Rake task in lib/tasks/:
namespace :db do
desc 'Make migration with output'
task(:migrate_with_sql => :environment) do
ActiveRecord::Base.logger = Logger.new(STDOUT)
Rake::Task['db:migrate'].invoke
end
end
Then call rake db:migrate_with_sql to log the migration.
3 Comments
Damon Aw
ActiveRecord::Base.logger = Logger.new(STDOUT) is the magic, getting a particular migration to run just involves setting the logger prior :)
Surya
This is brilliance
kkurian
This is fine but stackoverflow.com/a/8335695/972128 feels more elegant.
I put together the capture_migration_sql gem for this purpose. It will dump your migration SQL to files in db/migration_sql.
It's overkill if you just need to find a single SQL statement, but is great to have if your production process requires the raw SQL statements. It can also make reviewing complex database changes in code reviews a bit easier since there's no ruby -> SQL mental math required.
You can run preview SQL in rails console like this:
ActiveRecord::Base.connection.change_table(:events) do |t|
t.integer :submission_id, default: 5, null: false
end
#=> ALTER TABLE `events` ADD `submission_id` int DEFAULT 5 NOT NULL
So, just prepend your ordinary migration methods with ActiveRecord::Base.connection. and you are good to go.
There is also rails console --sandbox mode which rollbacks changes after you close the console. Though check if it works for your project, somehow for our project with rails 5 + MySQL it doesn't roll back DDL changes.
If you have migration files ready, you can also run it directly:
ActiveRecord::MigrationContext.new("db/migrate").migrate
ActiveRecord::MigrationContext.new("db/migrate").rollback
rails console --sandboxand then run migration from console. The SQL will be printed while it is being executed and everything should rollback when you exit the console