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copied!<p>You want <a href="http://api.rubyonrails.org/classes/ActiveRecord/Base.html#method-c-establish_connection" rel="noreferrer">ActiveRecord::Base#establish_connection</a>. You'll probably want to use it in an abstract subclass so that models using the manual connections don't disturb the connection uses by the rest of your application:</p> <pre><code>class LogBase < ActiveRecord::Base self.abstract_class = true end class LogItem < LogBase ... end LogItem.establish_connection { ... } LogItem.find_by_ ... </code></pre> <p>If you'll only ever have one model that makes manual connections the abstract class is unnecessary. </p> <p>Do you know the full set of databases that you might connect to? If so, database.yml may still be useful to you. You can put all the information in there as a directory, giving each database a name, then dynamically chose which one to establish_connection with in the application using those names:</p> <pre><code># database.yml atlanta: host: atlantadb.foo.com # foo.rb LogItem.establish_connection :atlanta </code></pre> <p>Setting up connections can be pretty heavyweight, doubly so if the sites are separated by wide area network. I'd consider whether it makes more sense to use an extract-transform-load approach and use a hourly/daily cron job to copy the data to a centralized reporting site. This is the most basic form of a data warehouse, and is a very commonly used approach. If you're using MySql, <a href="http://www.maatkit.org/tools.html" rel="noreferrer">Maatkit Sync</a> is a neat little tool, like rsync for tables. Alternately you probably use a database that supports master-slave replication, though that can be considerably more complicated to maintain.</p>

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