Multi-level Imports

[allenwlee]

The README strongly suggests that we can import multi-level objects, e.g.:

Say you had a schema like this:

Publishers have Books
Books have Reviews
and you wanted to bulk insert 100 new publishers with 10K books and 3 reviews per book. This library will follow the associations down and generate only 3 SQL insert statements - one for the publishers, one for the books, and one for the reviews.

where search has_many :tiers through: :searches_tiers
I've tried the following:

s=Search.new(name: 'Foo')
s.tiers << Tier.new(name: 'Bar')
Search.import [s]

search gets imported
tier does not

should this work?

Also, pull request #104 , although mainly about returning ids in Postgres, has a subconversation about multi-level importing, which was implemented in this fork by @GoodMeasuresLLC, now stale. Can someone please clarify whether multi-level import is available or not?

[johnnaegle]

Multilevel import does work, however, it is only implemented for autosave associations (I believe there is an issue or PR to change that behavior) and you need to import with :recursive => true

The tests have an example:

Topic.import new_topics, :recursive => true

I think if you change your has_many :tiers association, and maybe the :searches_tiers to be autosave true and add the recursive option to the import, you'll get tiers imported.

[allenwlee]

Thanks for your response @johnnaegle . You were right about the recursive: true, but I also needed to add inverse_of: to my model:

For Rails 4.2.0:
Models

class Search
  has_many :company_tiers_searches, inverse_of: :search, dependent: :destroy
end

class CompanyTiersSearch
  belongs_to :search
  validates_presence_of :search
end

then

s=Search.new(period_start: DateTime.now); 
s.company_tiers_searches.build(company_role_id: 4, company_tier_id: 1);
Search.import [s], recursive: true

successfully resulted in
#<struct ActiveRecord::Import::Result failed_instances=[], num_inserts=1, ids=["6912"]>

Note also that you will need to use validates_presence_of :search, rather than validating search_id, since you will be creating both Search and CompanyTiersSearch simultaneously and so there will be no extant search_id before save.