为什么Rails要求我一次又一次运行rake db：migrate RAILS_ENV = test？

Question

Could you help me with this issue:

When executing

root@myproject-dev:~/projects/myproject-dev$ rake db:migrate:status

database: myproject-db

 Status   Migration ID    Migration Name
--------------------------------------------------
   (...)
   up     20151104094107  Add need to something
   up     20151111082356  ********** NO FILE **********
   up     20151113024714  Add approved something
   up     20151116075224  Add something
   up     20151130041605  Change column name

root@myproject-dev:~/projects/myproject-dev$ bundle exec rspec

RSpec is shutting down and will print the summary report... Interrupt again to force quit.
/home/xxx/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:389:in `check_pending!':  (ActiveRecord::PendingMigrationError)

Migrations are pending. To resolve this issue, run:

        bin/rake db:migrate RAILS_ENV=test

Status show me everything is up and the rake db:migrate RAILS_ENV=test has already been performed correctly. If I execute it again I get errors (of course).

Why Rails ask me to run rake db:migrate RAILS_ENV=test again and again ?

Answer 1

There are 3+ default Rails environments:

• development
• production
• test

Each of them is supposed to have different settings, including different database to operate on. This is done to separate environments and prevent accidental data corruption/damage when running in inappropriate environment.

E. g. in test environment, every execution of rake test clears the database to prevent side effects . rspec automatically sets test environment for you.

So, in your case, you should migrate your test database :

RAILS_ENV=test rake db:migrate:status
RAILS_ENV=test rake db:migrate

Hope it helps.