Add Specific Column of Data from CSV to Heroku Table Without Affecting Existing Data

Question

I have a CSV with a list of user email addresses. I need to add these addresses as new records to my heroku user table without affecting the user rows that are already in there. The CSV is not currently in the same table format as the heroku table, it is simply one column of data.

I have tried a few methods, however they seem to start by removing the data that is currently in the table before importing. What is the best way to achieve this?

Email list is in same order as records there on heroku? Means first email in csv should match to 1st record in user table and so on ? — Nitin
– Nitin, Commented Sep 5, 2014 at 10:09
The email addresses are not for the current records. They are to be added as new records in the table. Each email address in my CSV should lead to one new record in my user table. They are in no particular order. — tob88
– tob88, Commented Sep 5, 2014 at 10:16
So simply create a seed file for this. How many column your csv file have ? — Nitin
– Nitin, Commented Sep 5, 2014 at 10:22

Nitin · Accepted Answer · 2014-09-05 10:32:23Z

1

considering you have csv with head "email"

Your seed file will look like :

require 'csv'

data = CSV.read(Rails.root.to_s + '/public/csvfile', headers: true)
data['email'].each do |email|
  @user = User.new(:email => email)
  User.save(:validate => false)
end

answered Sep 5, 2014 at 10:32

Nitin

7,3761 gold badge23 silver badges32 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

tob88 Over a year ago

After a few tweaks, this has worked perfectly. Thanks Nitin :)

Craig Ringer Over a year ago

It'll be horrifyingly slow for large user counts, though. If you want to do it efficiently, COPY the csv into a new table, then do an UPDATE ... FROM to do a joined update adding the new field.

Collectives™ on Stack Overflow

Add Specific Column of Data from CSV to Heroku Table Without Affecting Existing Data

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related