Use UUID as primary key in Rails On Rails

Use UUID as primary key in Rails On Rails

2019, Jan 05    

Recently with expected high scale projects, I started it by use UUID as the primary and foreign key of the tables. The result comes with a perfect high scale result. This methodology comes with bad and good effect. Even so, I recommend initing project with something like this if want to have easy and flexible scaling to your app in the future. Again, I really recommend this if you think of ↗️↗️↗️

Note: Tutorial below use specific between Ruby On Rails and Postgresql

Why should we use UUID?

  • Moving Data: UUID mean in this world your id is unique. That means it is easier to merge, split, or move data across table or event database
  • Multi location: When you million of transaction that you can not handle in one single database. So you need your database to have a master and the child nodes or place in multi-location, this will be handled when the database is synced because the primary is already unique across the database.
  • Talk to different app: When we have multiple apps that need to communicate with each other. Our records will have a unique identity
  • Security: No one can guess your previous or next record by decrease or increase the number because record id now is a random string
  • Able to generate your own id: Without sequence, you able create your own id with any string
  • No waiting insert: When you multiple insert at the same time you record don’t need to wait for next sequence. It will go directly into your database.

Bad side of it

  • Performance: Imagine that the primary key with a number of [1, 2, 3] now is changed to the stupid crazy string like 831a4357-3ac3-47bf-998e-4e4fae8d9150 it effects much on query performance
  • Ugly: UUID is a random string. Which it won’t look right if you include in URL or some user interactive

First what we need is enable pgcrypto plugin to Postgresql. this required as we to use gen_random_uuid to generate UUID primary when record is created.

We generate migration by run command

rails generate migration enable_pgcrypto

In your migration file

class EnablePgcryptoExtension < ActiveRecord::Migration[5.2]
  def change
    enable_extension 'pgcrypto'
  end
end


Add config to config/application.rb

...
config.generators do |g|
  g.orm :active_record, primary_key_type: :uuid
end
...

Now you able to use primary as UUID in your app. 👏👏👏


When create new model

Ruby on Rails Command to create new model

rails generate model product title:string

Your migration file will look like

class CreateProducts < ActiveRecord::Migration[5.2]
  def change
    create_table :products, id: :uuid do |t|
      t.string :title
      t.timestamps
    end
  end
end


Handle References

When you add your foreign key it, your migration file should look like

add_references :item, :user_id, :uuid
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