Multiple Active Record Connection

rubyonrails-talk
1

Dear all

My ActiveRecord::Base is connected to server_a (local server), has a Server model contains about 100 server records (remote server).

I use the following block to retrieve the server infomation. It works fine.

Server.find_all_by_server_type("sybase_t").each do |s|

    if s.server_name =~ /^LIS_..._ST1[0-2]/ and s.is_active?       class Order < ActiveRecord::Base         set_table_name = "orders"       end       Order.establish_connection s.connection_hash

      begin         puts "#{s.server_name} has #{Order.count} orders"       rescue         puts "#{s.server_name} is down"       end

    end end

I want to create another model OrderDetail in the remote server (see below code). It does not work. It said "TypeError: superclass mismatch for class OrderDetail".

Server.find_all_by_server_type("sybase_t").each do |s|     if s.server_name =~ /^LIS_..._ST1[0-2]/ and s.is_active?       class Order < ActiveRecord::Base         set_table_name = "orders"       end       Order.establish_connection s.connection_hash       class OrderDetail < ActiveRecord::Base         set_table_name = "order_detail"       end       OrderDetail.establish_connection s.connection_hash       begin         puts "#{s.server_name} has #{Order.count} orders and #{OrderDetail.count} order_detail"       rescue         puts "#{s.server_name} is down"       end     end end

I used google and find that the error will happen if the code like this http://railsforum.com/viewtopic.php?id=10993

   1. class Cool    2. end    3.    4. class SpecialCool < Cool    5. end    6.    7. class SpecialCool # this line will raise an error    8. end

How can I change my code so that I can have more than 1 models in the remote server?

Thank you very much Valentino

2

The error that you found in railsforum is probably on the right track. Is there any other declaration of the class OrderDetail other than what you have shown? If so, this is the problem. Also, if all of the servers in you server model have the same set of models, you may want to consider the following:

1) Create a RemoteModel class that inherits from ActiveRecord. This class will only be used for inheritance and to simplify connections. 2) Create "local" models for each model in the remote server. In your example, this would mean creating an order.rb and an order_details.rb 3) Each of the models created in step 2 should inherit from RemoteModel. From your example

class Order < RemoteModel end

4) Your code can then look like this

Server.find_all_by_server_type("sybase_t").each do |s|     if s.server_name =~ /^LIS_..._ST1[0-2]/ and s.is_active?       RemoteModel. establish_connection s.connection_hash       # Do remote model stuff here     end end

This approach DRY's up your code and kinda puts things where they belong.