Is it possible to mix migrations file without harmful consequences? - rails-migrations

Question

Let me explain :
I followed the M. Hartl tutorial and I did just like him with migrations. So now, I have the followings files in my db/migrate directory (I spare you the timestamps):
create_users.rb
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.string :email
t.timestamps
end
end
end
add_index_to_users_email.rb
class AddIndexToUsersEmail < ActiveRecord::Migration
def change
add_index :users, :email, unique: true
end
end
add_password_digest_to_users.rb
class AddPasswordDigestToUsers < ActiveRecord::Migration
def change
add_column :users, :password_digest, :string
end
end
add_remember_token_to_users.rb
class AddRememberTokenToUsers < ActiveRecord::Migration
def change
add_column :users, :remember_token, :string
add_index :users, :remember_token
end
end
add_admin_to_users.rb
class AddAdminToUsers < ActiveRecord::Migration
def change
add_column :users, :admin, :boolean, default: false
end
end
Is it possible to mix everything into create_users.rb like following, and delete the others migration files without any damage to my app ?
create_users.rb
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.string :email
t.string :password_digest
t.string :remember_token
t.boolean :admin, default: false
t.timestamps
end
add_index :users, :email, unique: true
add_index :users, :remember_token
end
end

Answer 1

Yes, it is possible. A straighforward strategy for that might be:
In order to avoid data loss, make a database dumb (create a DB backup)
Drop and recreate the database:
rake db:drop db:create
Have all migrations merged into a single file like you've shown
Run:
rake db:migrate
Restore the DB backup
Though, this may become tricky if you already have the application deployed on production.