How can I import a CSV file via a rake task?

问题

I know this question has been asked a lot on this forum but I'm under a strict deadline and I need some help, so any advice is much appreciated. I'm new to Ruby on Rails so please keep that in mind when responding. I want to create a rake task that, when run, updates multiple tables in mysqlite db. This is a migration file that creates a new incident in my db. How do I create a rake task that will input all this info via a CSV file. Can someone PLEASE give me some help in writing the rake file from start to finish. Obviously you don't need to write every task for every string, just give me a few examples. And besides the actual rake file, do I need to add code to any other part of my app (I know thats a very general question, but if I do need to add code, I would appreciate a general description of where). I feel a little bit of guidance will go along way. If anyone needs any more information from me please just ask.

class CreateIncidents < ActiveRecord::Migration
  def self.up
    create_table :incidents do |t|
      t.datetime :incident_datetime
      t.string :location
      t.string :report_nr
      t.string :responsible_party
      t.string :area_resident
      t.string :street
      t.string :city
      t.string :state
      t.string :home_phone
      t.string :cell_phone
      t.string :insurance_carrier_name
      t.string :insurance_carrier_street
      t.string :insurance_carrier_city
      t.string :insurance_carrier_state
      t.string :insurance_carrier_phone
      t.string :insurance_carrier_contact
      t.string :policy_nr
      t.string :vin_nr
      t.string :license_nr
      t.string :vehicle_make
      t.string :vehicle_model
      t.string :vehicle_year


      t.timestamps
    end
  end

  def self.down
    drop_table :incidents
  end
end

回答1:

under your project folder in lib/task create a rake file say "import_incidents_csv.rake"

follow this Ruby on Rails - Import Data from a CSV file

in rake file have following code

require 'csv'
namespace :import_incidents_csv do
  task :create_incidents => :environment do
    "code from the link"  
  end
end 

You can call this task as "rake import_incidents_csv:create_incidents"

回答2:

I worked on this for hours and hours one day. I finally got it to work by doing the following:

1. Added a header in the first row to my csv file that reflected the attr_accessible in my model. In my case my model was attr_accessible :intro, :name and in my csv file the first line read name, intro.
2. Created a custom rake file. I named mine import.rake and placed it in the lib/tasks folder. Place this code in that file:

#lib/tasks/import.rake
require 'csv'
desc "Imports a CSV file into an ActiveRecord table"
task :import, [:filename] => :environment do    
    CSV.foreach('myfile.csv', :headers => true) do |row|
      MyModel.create!(row.to_hash)
    end
end

Then type bundle exec rake import into the command line.

To get this to work I had quite SQLite Database Browser. I hope that helps someone!

回答3:

Here is an example CSV that I imported using rake db:seed. I wrote this into the seeds.rb file and put the CSV file into /public/seed_data/zip_code.csv. It's pretty self explanatory (i.e., the csv has three columns: code, long. and lat.

The code parses each line, extracts the pertinent data and assigns it to a local variable then writes it to a record. Hope it helps.

File.open("#{Rails.root}/public/seed_data/zip_code.csv") do |zip_codes|
  zip_codes.read.each_line do |zip_code|
    code, longitude, latitude = zip_code.chomp.split(",")
    #  to remove the quotes from the csv text:
    code.gsub!(/\A"|"\Z/, '')
    # to create each record in the database
    ZipCodeGeo.create!(:zip_code => code, :longitude => longitude, :latitude =>      latitude)             
  end
end

回答4:

You can read your csv file using CSV module of rails and can create records. Here is detailed help: Populate db using csv

回答5:

I've used this one in the past. It takes any type of model.

rake csv_model_import[bunnies.csv,Bunny]

Works like a charm.

desc "Imports a CSV file into an ActiveRecord table"
task :csv_model_import, :filename, :model, :needs => :environment do |task,args|
  lines = File.new(args[:filename]).readlines
  header = lines.shift.strip
  keys = header.split(',')
  lines.each do |line|
    params = {}
    values = line.strip.split(',')
    keys.each_with_index do |key,i|
      params[key] = values[i]
    end
    Module.const_get(args[:model]).create(params)
  end
end

来源：https://stackoverflow.com/questions/12461260/how-can-i-import-a-csv-file-via-a-rake-task