Validate unique array values in Rails - ruby-on-rails

Question

My Transaction model generates an array of unique ticket numbers based on quantity (an integer column) with the following controller logic:
#transaction.quantity.times.uniq { #transaction.ticket_numbers << rand(100000..999999) }
However, this only ensures that the numbers WITHIN the array are unique.
I need a database validation that checks ALL Transaction.ticket_numbers arrays to ensure that every value (ticket number) is unique across ALL arrays.
Here is my Transaction table within schema.rb:
create_table "transactions", force: :cascade do |t|
t.string "payee"
t.integer "quantity"
t.decimal "debt", precision: 8, scale: 2
t.string "email"
t.string "ministry"
t.integer "status"
t.integer "user_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "ticket_numbers", default: [], array: true
end
Transaction model from transaction.rb:
require 'csv'
class Transaction < ApplicationRecord
belongs_to :user
validates :email, :format => { :with => /\A([^#\s]+)#((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/, :on => [:create, :update] }
validates :payee, presence: true
validates :quantity, numericality: { greater_than_or_equal_to: 1 }
validates :debt, numericality: { greater_than_or_equal_to: 0 }
def self.to_csv
attributes = %w{payee email ministry quantity debt status ticket_numbers}
CSV.generate(headers: true) do |csv|
csv << attributes
all.each do |transaction|
csv << attributes.map{ |attr| transaction.send(attr) }
end
end
end
end
Transaction controller:
class TransactionsController < ApplicationController
before_action :load_transaction, only: [:edit, :update, :destroy]
def create
#transaction = Transaction.new(transaction_params)
if #transaction.save
#transaction.quantity.times.uniq { #transaction.ticket_numbers << rand(100000..999999) }
end
#user = #transaction.user
#transactions = #user.transactions
respond_to do |format|
if #transaction.save && #transaction.status == 1
UserMailer.payment_confirmation(#transaction).deliver_later
format.html { redirect_to user_url(#user), notice:'Transaction added & ticket sent' }
format.json { render json: #user, status: :created, location: #user }
elsif #transaction.save && #transaction.status != 1
format.html { redirect_to user_url(#user), notice:'Transaction added' }
format.json { render json: #user, status: :created, location: #user }
else
format.html { render 'users/show' }
format.json { render json: #transaction.errors, status: :unprocessable_entity }
end
end
end
def edit
#user = current_user
end
def update
update_ticket_numbers
respond_to do |format|
if #transaction.update_attributes(transaction_params) && #transaction.status == 1
UserMailer.payment_confirmation(#transaction).deliver_later
format.html { redirect_to user_url(current_user), notice: 'Transaction info updated & confirmation email sent to payee' }
format.json { render json: current_user, status: :created, location: current_user }
elsif #transaction.update_attributes(transaction_params) && #transaction.status != 1
format.html { redirect_to user_url(current_user), notice: 'Transaction info updated' }
format.json { render json: current_user, status: :created, location: current_user }
else
format.html { render :edit }
format.json { render json: #transaction.errors, status: :unprocessable_entity }
end
end
end
def destroy
#transaction.destroy
redirect_to user_url(current_user), notice: 'Transaction deleted'
end
private
def load_transaction
#transaction = Transaction.find(params[:id])
end
def transaction_params
params.require(:transaction).permit(:payee, :email, :ministry, :debt,
:quantity, :status, :user_id, :ticket_numbers)
end
def update_ticket_numbers
if #transaction.update_attributes(transaction_params)
if #transaction.ticket_numbers.length < #transaction.quantity
i = #transaction.quantity - #transaction.ticket_numbers.length
i.times.uniq { #transaction.ticket_numbers << rand(100000..999999) }
elsif #transaction.ticket_numbers.length > #transaction.quantity
i = #transaction.ticket_numbers.length - #transaction.quantity
i.times { #transaction.ticket_numbers.pop }
end
end
end
end

Answer 1

You can add a custom ticket number validation to your model. You can read more about them here
class Transaction < ApplicationRecord
validate :ticket_number_uniqueness
def ticket_number_uniqueness
# First check all new ticket numbers are unique from each other
errors.add(:ticket_number, "is not unique") unless ticket_numbers == ticket_numbers.uniq
# Next check against other ticket numbers
ticket_numbers.each do |ticket|
if ::Transaction.where("ticket_numbers #> '{?}'", ticket).exists?
errors.add(:ticket_number, "is not unique")
end
end
end
end
Note: this is taking advantage of Postgres contains array method #>. You can learn more about array methods here