okabe-yuya

• TODO
  • A
  • B
• C

okabe-yuya

BEGIN;
CREATE TABLE IF NOT EXISTS students (
  student_id SERIAL PRIMARY KEY,
  first_name VARCHAR(30) NOT NULL,
  last_name VARCHAR(30) NOT NULL,
  birthday DATE NOT NULL,
  gender CHAR(1),
  created_at TIMESTAMP,
  updated_at TIMESTAMP
);

okabe-yuya

defmodule StateServer do
  @transitions %{
    initial: %{ receive_order: :check_stock },
    check_stock: %{ purchase: :ready_for_snipment },
    ready_for_snipment: %{ snipment: :package_arrive },
    package_arrive: %{ initial: :initial }
  }

  def run do
    spawn(fn -> server(:initial) end)

okabe-yuya

require 'benchmark'

list = (1..10000).to_a
Benchmark.bm(20) do |x|
  x.report('for:') do
    hash = {}
    for n in list do
      hash[n.to_s] = n * 2
    end
  end

okabe-yuya

JOINのみ

EXPLAIN ANALYZE SELECT
  *
FROM
  user_products AS up
JOIN
  users AS u
ON

okabe-yuya

table

BEGIN;
  CREATE TABLE IF NOT EXISTS users (
    user_id SERIAL PRIMARY KEY,
    user_name VARCHAR(50) NOT NULL
  );
  CREATE TABLE IF NOT EXISTS products (
 product_id SERIAL PRIMARY KEY,

okabe-yuya

検証結果

中間テーブルの情報。現在はインデックスはuser_product_idにのみ付与。

                                       Table "public.user_products"
     Column      |  Type   | Collation | Nullable |                        Default                         
-----------------+---------+-----------+----------+--------------------------------------------------------
 user_product_id | integer |           | not null | nextval('user_products_user_product_id_seq'::regclass)
 user_id         | integer |           |          | 
 product_id      | integer |           |          | 

okabe-yuya

# ref: https://www.paweldabrowski.com/articles/rails-enum-under-the-hood

module Channel
  def enum_channels(mappings)
    mappings.each_pair do |name, values|
      singleton_class.define_method("#{name}_hash") { values }

      values.each_pair do |key, value|
        define_method("#{key}?") { self.status == value  } 
      end

okabe-yuya

/* プレイヤー情報 */
CREATE TABLE IF NOT EXISTS players (
  player_id SERIAL PRIMARY KEY,
  name VARCHAR(50) NOT NULL,
  created_at TIMESTAMP NOT NULL,
  updated_at TIMESTAMP NOT NULL,
  name_changed_at TIMESTAMP NOT NULL,
  last_loggined_at TIMESTAMP NOT NULL
);

okabe-yuya

/* プレイヤー情報 */
CREATE TABLE IF NOT EXISTS players (
  player_id SERIAL PRIMARY KEY,
  name VARCHAR(50) NOT NULL,
  created_at TIMESTAMP NOT NULL,
  updated_at TIMESTAMP NOT NULL,
  name_changed_at TIMESTAMP NOT NULL,
  last_loggined_at TIMESTAMP NOT NULL
);