How to delete all data from all tables in Rails?

Solution 1:

rake db:reset 

It recreates your table from migrations.

As suggested in the comments, a faster way to do it (but you have to add a new rake task) is:

namespace :db do
  desc "Truncate all tables"
  task :truncate => :environment do
    conn = ActiveRecord::Base.connection
    tables = conn.execute("show tables").map { |r| r[0] }
    tables.delete "schema_migrations"
    tables.each { |t| conn.execute("TRUNCATE #{t}") }
  end
end

Response copied from: answer on SO.

Solution 2:

You can have finer control with:

rake db:drop:all

And then create the database without running the migrations,

rake db:create:all

Then run all your migrations,

rake db:migrate 

You can also do:

mysqladmin drop databasename

Solution 3:

If you're trying to do this from code instead of the command line, say from a Test::Unit::TestCase#teardown method, you could do either

class MyTest < Test::Unit::TestCase

  def teardown
    ActiveRecord::Base.subclasses.each(&:delete_all)
  end

end

or

class MyTest < Test::Unit::TestCase

  def teardown
    Rake::Task['db:reset'].invoke
  end

end

I warn you, though: neither is particularly fast. You're definitely better off with transactional tests if you can.

Solution 4:

If you simply want to start fresh with a fresh set of empty tables, you can first ensure you have an up-to-date definition of the schema in db/schema.rb:

rake db:schema:dump

and then:

rake db:schema:load

which has the effect of dropping tables and then re-creating them, without running through your entire battery of migrations.