Multiple database connection in Rails

Sanal picture Sanal · Aug 19, 2009 · Viewed 16.8k times · Source

I'm using active_delegate for multiple connection in Rails. Here I'm using mysql as master_database for some models,and postgresql for some other models.

Problem is that when I try to access the mysql models, I'm getting the error below! Stack trace shows that, it is still using the postgresql adapter to access my mysql models!

RuntimeError: ERROR C42P01  Mrelation "categories" does not exist   P15 F.\src\backend\parser\parse_relation.c  L886    RparserOpenTable: SELECT * FROM "categories" 

STACKTRACE
===========
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:507:in `execute'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:985:in `select_raw'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/postgresql_adapter.rb:972:in `select'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:81:in `cache_sql'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in `select_all'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:661:in `find_by_sql'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:1553:in `find_every'
d:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:615:in `find'
D:/ROR/Aptana/dedomenon/app/models/category.rb:50:in `get_all_with_exclusive_scope'
D:/ROR/Aptana/dedomenon/app/models/category.rb:50:in `get_all_with_exclusive_scope'
D:/ROR/Aptana/dedomenon/app/controllers/categories_controller.rb:48:in `index'

here is my database.yml file

postgre: &postgre
  adapter: postgresql
  database: codex
  host: localhost
  username: postgres
  password: root
  port: 5432  

mysql: &mysql
  adapter: mysql
  database: project
  host: localhost
  username: root
  password: root
  port: 3306  

development:
  <<: *postgre

test:
  <<: *postgre

production:
  <<: *postgre

master_database:
  <<: *mysql

and my master_database model is like this

class Category < ActiveRecord::Base

  delegates_connection_to :master_database, :on => [:create, :save, :destroy]

end

Anyone has any solution??

Answer

Hoang Tran picture Hoang Tran · Dec 10, 2010

Another way:

class Abc < ActiveRecord::Base
  establish_connection Rails.configuration.database_configuration["test"]
end