I want to import the pull-down menu items when submitting a form in Rails into CSV and display them from the DB data.

Introduction

It is a memorandum for CSV importing pull-down menu items when submitting a form in Rails and displaying them using DB data.

environment

• macOS 10.15.6
• Ruby 2.5.7
• Rails 5.2.3
• rspec-rails 4.0.1
• capybara 3.32.2

Reference URL

CSV import related https://qiita.com/Ryuta1346/items/c21cb70b9879c66c8639 https://qiita.com/SoarTec-lab/items/50e046ea2a2764c12c21 https://docs.ruby-lang.org/ja/latest/class/CSV.html https://qiita.com/3yatsu/items/416411c0a8f696dbf99e https://qiita.com/rllllho/items/672e336a03335cba6b34

Pull-down menu related https://qiita.com/HrsUed/items/56677d6c266d8a53ffa7 https://qiita.com/kawakami_shotaro/items/11a677bf34136cb7686d https://qiita.com/colorrabbit/items/b58888506e41d1370fd1 https://crieit.net/posts/Rails-collection-select https://qiita.com/_akira19/items/c218186983f444c2d794

Country code list CSV https://qiita.com/tao_s/items/3yy2b90a2751bfbdd585ea

Target

1. CSV import pull-down menu choices
2. Display the selection items in the pull-down menu using the DB data

It is an image of appearance ↓

The pull-down menu choices are displayed using the column information saved in the DB ↓

Implementation

I will explain CSV import and form pull-down separately.

1. CSV import pull-down menu choices

1. Create Country model for saving country name list
2. Add import process to db / seeds.rb
3. Execute the import process with the rails command

The import process is performed using the CSV library of Ruby. This time, I imported the country name list from the following CSV. I added the created CSV file to the root directory.

country.csv

number,Country / region name,ISO 3166-English name in 1,number,Three characters,Two letters,place,Each administrative division
1,Iceland,Iceland,352,ISL,IS,Northern Europe,ISO 3166-2:IS
2,Ireland,Ireland,372,IRL,IE,Western Europe,ISO 3166-2:IE

For CSV, I used Country Code List CSV.

1. Country model creation

I created the following model. The region column is not used this time.

#Country modeling
$ rails g model Country country_name:string region:string

2. Add import process

The import process has been added to seeds.rb. There seems to be a separate file and How to execute with runner command.

seeds.rb

require "csv"

#Specify the path to the CSV file as an absolute path
CSV.foreach("country.csv", headers: true) do |row|
  Country.create!(
    country_name: row["Country / region name"],
    region: row["place"]
  )
end

3. Execute the import process

Perform a CSV import with the rails command. I also wrote other processing in the seed file, so this time I deleted everything in the DB and imported it again.

#This is all you need to import a CSV and save it to your DB
$ rails db:seed

#Erase the DB and reinsert everything
$ rails db:migrate:reset
$ rails db:seed

#Check if it was imported in the rails console
$ rails c
#Check the number of imported country names
> Country.count
249

2. Display the selection items in the pull-down menu using the DB data

Modify the View file of the form submission at the time of new posting.

Ruby:view/model_names/new.html.erb

#Before correction
<%= form_with model: @model_name do |f| %>
  <%= f.label :country %>
  <%= f.text_field :country %>

  <%= f.submit "Send" %>
<% end %>

Ruby:view/model_names/new.html.erb

#Revised
<%= form_with model: @model_name do |f| %>
  <%= f.label :country %>
  <%= f.collection_select :country, Country.all, :id, :country_name, prompt: "Please select a country" %>

  <%= f.submit "Send" %>
<% end %>

# collection_select syntax
<%= f.collection_select <Column name of save destination>, <Array data for display>, <Column name of the value to save>,  <Column name for display>, <option> %>

• Destination column name: country
• Array data for display: Country.all
• Column name of the value to save: id
• Column name for display: country_name
• Optional: Show Please select a country with prompt option`

Here The explanation about how to use collection_select is very easy to understand.

Learn

• Import in consideration of subsequent processing such as search
• Since the options will be long vertically, I would like to change to use in consideration of ease of use, such as by giving a hierarchy.