ipums/mound

mound (formerly rabl)

Ruby bulk loader, with clever foreign key support. mound was developed with funding from the National Science Foundation

Quick Tutorial

RABL deals with data described via YAML, and uses your ActiveRecord models to load the data. Assuming you have an ActiveRecord model class named invoice_type, with an attribute named name, like so:

class InvoiceType < ActiveRecord::Base
  attr_accessible :name
end

then you could populate the table with three records like this:

invoice_types:
  -
    name: cash
  -
    name: credit
  -
    name: singleton

Internally, RABL will create three instances of the invoice_type model and save them. The usual active record behaviour applies, in that you'll also have an id column on your model and AR or the database will assign an arbitrary primary key for you.

This is useful, but not that different from what you can do with fixtures. Things get more interesting when you have data with relationships. Let's consider adding an invoice model as well. Each invoice, of course, has an invoice_type to go with it.

Here's our invoice.rb class:

class Invoice < ActiveRecord::Base
  belongs_to :invoice_type
  attr_accessible :description, :price
end

and we'll need to update invoice_type.rb to reflect the one-to-many relationship:

class InvoiceType < ActiveRecord::Base
  attr_accessible :name
  has_many :invoices
end

Now, the invoice_type import file doesn't change, but we can also load invoices and set up the foreign key properly by referring to the invoice_type by name, like so:

invoices:
  - 
    name: one
    description: basic
    price: 9.99
    invoice_type_id: cash
  - 
    name: two
    description: with child items
    price: 19.99
    invoice_type_id: credit
  -
    name: highlander
    description: Why is this named highlander? Beacuse there should only be one.
    price: 0.00
    invoice_type_id: singleton