This gem adds ActiveRecord support for partitioned has_one relations using the PostgreSQL PARTITION BY clause.
Add this line to your application's Gemfile:
gem 'hmp'
And then execute:
$ bundle
Or install it yourself as:
$ gem install hmp
Suppose you have some Customers, and each Customer has_many SupportTickets. If SupportTicket has a created_at field, then it might be necessary to ask not just for
customer.support_tickets
but rather to ask for
customer.latest_support_ticket
Going 1 Customer at the time, you could easily do
customer.support_tickets.first(:order => 'id DESC')
but you could not include the association when you load the Customers because the ORDER BY clause should apply within each unique SupportTicket.customer_id, not over the whole set of Customers. Using the hmp gem adds support for, e.g.,
Customer.all(:limit => 10, :include => :latest_support_ticket)
In the Customer model, just add
include HasManyPartitionable
has_one_partitionable :latest_support_ticket
Other standard has_one options are supported, so if you wanted to use the name :most_recent_support_ticket instead, you could use
include HasManyPartitionable
has_one_partitionable :most_recent_support_ticket, :class_name => 'SupportTicket'
If :class_name is not given, a class name will be generated by removing every character up to and including the first underscore.
To run the tests, use
rspec
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request