生产中的数据库连接问题

Question

I have a separate DB for one model in my application and in development mode the connection is working properly, in production however it isn't.

production:
  adapter: mysql
  host: myhost
  username: root
  password:
  database: production_db

users_production:
  adapter: mysql
  host: myhost
  username: root
  password:
  database: other_db

The model that connects to the other database is called User but the table it references in other_db is smf_users so my User.rb looks like this:

class User < ActiveRecord::Base
  establish_connection "users_#{RAILS_ENV}"
  set_table_name "smf_users"
end

In production I'm getting this error:

Mysql::Error: Table 'production_db. smf_users' doesn't exist:

Note how it is trying to connect to the wrong database and so isn't finding the correct table. As I say, this works in development mode.

Any suggestions?

Answer 1

I've found when using multiple databases that odd errors show up when doing associations. Any chance you've got another model out there which belongs_to :users and you're expecting it to Just Work? Otherwise, you have to look at caching -- it's easily possible that Rails is failing to cache the connection data for your extra database correctly.

Answer 2

Try:

establish_connection configurations[RAILS_ENV]["users_#{RAILS_ENV}"]
User.connection

establish_connection needs a hash of the connection information. This should return if from database.yml.

You might want to check your log for a message like the following:

"users_production database is not configured"

That message would be thrown by ActiveRecord::Base if it can't find the congifuration by string in database.yml.

Answer 3

您可能会发现这很有用： http : //magicmodels.rubyforge.org/magic_multi_connections/