postgres

class FeatureFlag < ApplicationRecord
  validates :key, presence: true, uniqueness: true
  validates :percentage, inclusion: { in: 0..100 }

  after_commit :expire_cache

CREATE TABLE outbox (
    id             BIGSERIAL PRIMARY KEY,
    aggregate_type TEXT        NOT NULL,
    aggregate_id   TEXT        NOT NULL,
    event_type     TEXT        NOT NULL,
    payload        JSONB       NOT NULL,

class CreateProcessedEvents < ActiveRecord::Migration[7.1]
  def change
    create_table :processed_events do |t|
      t.string :event_key, null: false
      t.string :job_class, null: false
      t.jsonb :metadata, null: false, default: {}

class CreateUsers < ActiveRecord::Migration[7.1]
  def change
    create_table :users do |t|
      t.string :name, null: false

      # Ciphertext is larger than plaintext, so use text columns.

class Document < ApplicationRecord
  belongs_to :owner, class_name: "User"
  has_many :visibilities, class_name: "DocumentVisibility", dependent: :delete_all

  scope :public_documents, -> { where(is_public: true) }

class ReindexCheckpoint < ApplicationRecord
  enum status: { idle: 0, running: 1, done: 2, failed: 3 }

  validates :index_name, presence: true, uniqueness: true

  def self.for(index_name)

class CreateInventoryReservations < ActiveRecord::Migration[7.1]
  def change
    create_table :inventory_items do |t|
      t.string  :sku, null: false
      t.integer :quantity_on_hand,  null: false, default: 0
      t.integer :quantity_reserved, null: false, default: 0

import { Pool, PoolClient, Client, QueryResult, QueryResultRow } from 'pg';

const MAX_LIFETIME_MS = 30 * 60 * 1000;

export const pool = new Pool({
  connectionString: process.env.DATABASE_URL,

module Middleware
  class DatabasePinning
    PIN_WINDOW = 5.seconds

    def initialize(app)
      @app = app

module WriteAmplificationGuard
  extend ActiveSupport::Concern

  def update_if_changed(attrs)
    changed = attrs.each_with_object({}) do |(key, value), acc|
      cast = self.class.type_for_attribute(key.to_s).cast(value)

class CreateTags < ActiveRecord::Migration[7.0]
  def change
    create_table :tags do |t|
      t.string :name, null: false
      t.integer :taggings_count, null: false, default: 0
      t.timestamps

class AddOptimisticLockingToDocuments < ActiveRecord::Migration[7.1]
  def change
    add_column :documents, :lock_version, :integer, null: false, default: 0
    add_index :documents, :updated_at
  end
end