importing csv into ruby but need to create relationship - ruby-on-rails

Question

I am wanting to import 2 files (County & State). When I import I need to create a relationship with County to State.
My State CSV file has:
id
state e.g. "Connecticut"
abbreviation e.g. "CT"
My County CSV file has:
id
name e.g. "Hartford"
market_state e.g. "Connecticut"
The attributes for MarketCounty are:
create_table "market_counties", force: :cascade do |t|
t.string "name"
t.integer "market_state_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
The attributes for MarketState are:
create_table "market_states", force: :cascade do |t|
t.string "name"
t.string "abbreviation"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
My models have these relationships:
MarketState:
class MarketState < ActiveRecord::Base
has_many :market_reports, as: :location
has_many :market_cities
has_many :market_zips
has_many :market_counties
end
MarketCounty:
class MarketCounty < ActiveRecord::Base
has_many :market_reports, as: :location
has_many :market_cities
has_many :market_zips
belongs_to :market_state
end
My Rake task:
def import_market_states
MarketState.create!(name: "Connecticut", abbreviation: "CT")
end
def import_market_counties
path = Rails.root.join("config/csv/locations/counties.csv")
CSV.foreach(path, headers: true) do |row|
MarketCounty.create! row.to_hash
end
My question is in the the method import_market_counties, row.to_hash does not work.
ActiveRecord::AssociationTypeMismatch: MarketState(#70157557268540)
expected, got String(#70157439770720)
I set it up manually:
MarketCity.create!(name: "Hartford", market_state: MarketState.find_by(abbreviation: "CT")
How can I do a "lookup" in a loop when importing County file (to associate it to the MarketState model)?
To clarify, the issue is that when I am creating the County, I am not trying to populate state with CT. I need to populate state_id with the association.
I found this SO: When importing a CSV, how do I handle data in a row that corresponds to an association? ---
And thinking it may be similar to what I am trying to do - just not sure how to apply it here.

Answer 1

Assuming your MarketState has a name column that is the name of the state:
def import_market_counties
path = Rails.root.join("config/csv/locations/counties.csv")
CSV.foreach(path, headers: true) do |row|
MarketState.find_by_name( row['market_state'].strip )
end
you can also use find_or_create_by if you want to create the state if it doesn't exist.