Question

I can do Post.delete_all to delete all my posts, but what if I want to delete all posts, comments, blogs, etc.?

How do I iterate over all my models and run the delete_all method?

Answer 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.