NoMethodError: undefined method `needs_migration?' for ActiveRecord::Migrator:Class

Question

我收到以下错误消息，不确定如何解决。有人可以帮忙吗？

NoMethodError: undefined method `needs_migration?' for ActiveRecord::Migrator:Class

这里是 config.ru 代码：

require './config/environment'

if ActiveRecord::Migrator.needs_migration?
  raise 'Migrations are pending. Run `rake db:migrate` to resolve the issue.'
end

use Rack::MethodOverride

use UsersController
use ArtworkController
run ApplicationController

Answer 1

将您的代码更改为

if ActiveRecord::Base.connection.migration_context.needs_migration?
  raise 'Migrations are pending. Run `rake db:migrate` to resolve the issue.'
end