🛤️ Ruby on Rails -

PostgreSQL Arrays

Ruby on Rails supports PostgreSQL arrays out of the box.

class AddNicknamesToUser < ActiveRecord::Migration
  def change
    change_table :users do |t|
      t.text :nicknames, array: true, default: []
    end
  end
end

user = User.find(1)
user.update_attributes(nicknames: ['Ruksi'])
user.update_attributes(nicknames: user.nicknames.push('Ruxjin'))

# array contains this array
User.where('nicknames @> ARRAY[?]', ['Johnny'])          # no
User.where('nicknames @> ARRAY[?]', ['Ruxjin'])          # matches
User.where('nicknames @> ARRAY[?]', ['Doe', 'Ruxjin'])   # no
User.where('nicknames @> ARRAY[?]', ['Ruksi', 'Ruxjin']) # matches

# array contains a single element from this array, overlap
User.where('nicknames && ARRAY[?]', ['Doe', 'Ruxjin', 'Johnny']) # matches

# is column is any of the following values
User.where('name = ANY(ARRAY[?])', ['John Doe', 'Ruksi Laine'])  # matches

# if you defined column as string, you must covert the array to varchar[]
#User.where('nicknames @> ARRAY[?]::varchar[]', ['Doe', 'Ruxjin'])