Rails import csv to database in a model

Question

I search to load some csv file in my database, I'm using postgres. For this I got this method in my model

class Station < ApplicationRecord
  def self.import_from_csv()
    CSV.foreach('resources/locations.csv', headers: true) do|row|                                                                 
      station = Station.new(
        id: row[0].to_i,
        name: row['Name'],
        city: row['City'],
        default_dest: row['Default dest'],
        public: row['Public'] == 'true',
        lat: row['Lat'].to_f,
        long: row['Long'].to_f
      ).save!
    end
  end
end

And this in my controller

def index
  respond_to do |format|
    format.html {
      @stations = Station.all
      render
    }
    format.json {
      @total = Commute.count
      @commutes = Commute.filter(params)
      render
    }
  end
end

and this in my schema.rb

create_table "stations", force: :cascade do |t|
  t.string   "name",         null: false
  t.string   "city",         null: false
  t.float    "lat",          null: false
  t.float    "long",         null: false
  t.boolean  "public",       null: false
  t.string   "default_dest"
  t.datetime "created_at",   null: false
  t.datetime "updated_at",   null: false
end

But no data is loaded into my db.

Does someone know if there is a rake command that I have to run or something like this?

any errors on your server logs ?

Alok Swain
– Alok Swain

2016-08-10 10:11:43 +00:00
Commented Aug 10, 2016 at 10:11 — Alok Swain
– Alok Swain, Commented Aug 10, 2016 at 10:11

coorasse · Accepted Answer · 2021-03-01 16:20:02Z

2

Updated answer for Rails 6.x

Rails now supports insert_all, so you don't need the activerecord-import gem.

def self.import_from_csv
  stations = CSV.foreach('resources/locations.csv', headers: true).map do |row|                                                                 
  { 
    id: row[0].to_i,
    name: row['Name'],
    city: row['City'],
    default_dest: row['Default dest'],
    public: row['Public'] == 'true',
    lat: row['Lat'].to_f,
    long: row['Long'].to_f
  }
  end
  Station.insert_all(stations)
end

Old answer

You can hypotetically continue on this way and I would replace Station.new(...).save! with Station.create!(...).

You will soon face a problem in terms of time. If you are importing many records you approach will take reaaaally long. Please use activerecord-import gem and do that:

class Station < ApplicationRecord

  def self.import_from_csv
    stations = CSV.foreach('resources/locations.csv', headers: true).map do |row|                                                                 
      Station.new(
        id: row[0].to_i,
        name: row['Name'],
        city: row['City'],
        default_dest: row['Default dest'],
        public: row['Public'] == 'true',
        lat: row['Lat'].to_f,
        long: row['Long'].to_f
      )
    end
    Station.import(stations)
  end
end

edited Mar 1, 2021 at 16:20

answered Aug 10, 2016 at 10:19

coorasse

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5 Comments

maluss Over a year ago

Thank you I do this with changing the new by create and using this gem and then I restart my server but nothing change...

maluss Over a year ago

Why this will be long ? This will be executed every time that I use the app or just the first time?

lusketeer Over a year ago

@maluss he meant it would be long if you stick with your initial approach. The method will only run when you call it

maluss Over a year ago

there is a way to call it in the rails console? I try this : Station.import_from_csv but it's tell me uninitialized constant Station::CSV

coorasse Over a year ago

Did you add require 'csv' in config/application.rb?

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