ruby-on-rails - 为什么不同的 rake 命令会影响不同的数据库？

Question

当未指定RAILS_ENV 时，db:create 和db:drop 会同时影响开发和测试。然而在同样的情况下，db:migrate 只影响开发。这是为什么？

Answer 1

这是因为 test 数据库仅在测试运行时通过 schema.rb 更新。

参见 here :

In order to run your tests, your test database will need to have the current structure. The test helper checks whether your test database has any pending migrations. If so, it will try to load your db/schema.rb or db/structure.sql into the test database. If migrations are still pending, an error will be raised. Usually this indicates that your schema is not fully migrated. Running the migrations against the development database (bin/rake db:migrate) will bring the schema up to date.