Rails : Import CSV data to database

Actually there are various ways to achieve this. Firstly you can use the PostGreSQL’s copy command. Secondly you can choose to use Ruby to load data.

Using copy command in PG

Create your table:

CREATE TABLE zip_codes 
(ZIP char(5), LATITUDE double precision, LONGITUDE double precision, 
CITY varchar, STATE char(2), COUNTY varchar, ZIP_CLASS varchar);

Copy data from your CSV file to the table:

COPY zip_codes FROM '/path/to/csv/ZIP_CODES.txt' DELIMITER ',' CSV;

You can also specify the columns to read:

\copy zip_codes(ZIP,CITY,STATE) FROM '/path/to/csv/ZIP_CODES.txt' DELIMITER ',' CSV

 

Using Ruby

# == Schema Information
#
# Table name: vehicles
#
#  id         :integer          not null, primary key
#  fuelType   :string
#  make       :string
#  model      :string
#  range      :string
#  rangeCity  :string
#  year       :string
#  VClass     :string
#  cylinders  :string
#  displ      :string
#  created_at :datetime         not null
#  updated_at :datetime         not null
#

class Vehicle < ApplicationRecord
  def self.import!
    CSV.foreach(Rails.root.join('db/vehicles.csv'), headers: true) do |row|
      Vehicle.create! row.to_hash.slice('fuelType', 'make', 'model', 'range', 'rangeCity', 'year', 'VClass', 'cylinders', 'displ')
      print '.'.green
    end
  end
end
# lib/tasks/load_vehicle_data.rake
desc 'Loads data from db/vehicles.csv file to vehicles table'
task :load_vehicle_data => :environment do
  MyLogger.log('Starting to load the vehicle data from db/vehicles.csv ...')
  
  Vehicle.import!

  MyLogger.log('Done loading the vehicle data from db/vehicles.csv!')
end

 

If you choose to beautify the Log then you can use this

# app/models/concerns/my_logger.rb
module MyLogger
  def log(message, message_color: :green)
    puts '~'.yellow.bold * 100
    puts "DateTime: #{DateTime.now}"
    puts '~'.yellow.bold * 100
    puts message.try(message_color)
    puts '~'.yellow.bold * 100
  end

  module_function :log
end

For colorful CGI I have used this code in initializers

# config/initializers/string_modifier.rb
class String
  def black; "\e[30m#{self}\e[0m" end
  def red; "\e[31m#{self}\e[0m" end
  def green; "\e[32m#{self}\e[0m" end
  def blue; "\e[34m#{self}\e[0m" end

  def bold; "\e[1m#{self}\e[22m" end
  def italic; "\e[3m#{self}\e[23m" end
  def underline; "\e[4m#{self}\e[24m" end
  def blink; "\e[5m#{self}\e[25m" end
  def reverse_color; "\e[7m#{self}\e[27m" end
end
# note: if you use awesome_print gem, these methods will be auto-included

 

Screenshot from 2017-02-09 09-30-49.png

 

Sources

http://stackoverflow.com/questions/2987433/how-to-import-csv-file-data-into-a-postgresql-table

 

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