Sequel playground

sequel_playground.rb

#!/usr/bin/env ruby
require 'sequel'
require 'logger'
require 'awesome_print'

DB = Sequel.sqlite

DB.create_table :people do
  primary_key :id
  String :name
end

DB.create_table :posts do
  primary_key :id
  Integer :person_id
  String :title
end

class Person < Sequel::Model
  one_to_many :posts, eager: [:tags]
end

class Post < Sequel::Model
  many_to_one :person
  one_to_many :replies
  many_to_many :tags
end

class Tag < Sequel::Model
  many_to_many :posts
  many_to_many :replies
end

class Reply < Sequel::Model
  many_to_one :person
  many_to_one :post
  many_to_many :tags
end

person = Person.create(name: 'Bart')
Post.create(person: person, title: 'Hello')
Post.create(person: person, title: 'Hello 2')

person2 = Person.create(name: 'Homer')
Post.create(person: person2, title: 'Woohoo')

DB.loggers << Logger.new($stdout)

# === Main ===

Post.all.each{|post| ap [post.person.name, post.title]}

print "\n====================\n\n"

Post.eager(:person).all.each{|post| ap [post.person.name, post.title]}

Output:

I, [2016-04-06T17:16:44.655838 #7332]  INFO -- : (0.000071s) SELECT * FROM `posts`
I, [2016-04-06T17:16:44.656046 #7332]  INFO -- : (0.000069s) SELECT * FROM `people` WHERE `id` = 1
[
    [0] "Bart",
    [1] "Hello"
]
I, [2016-04-06T17:16:44.656309 #7332]  INFO -- : (0.000048s) SELECT * FROM `people` WHERE `id` = 1
[
    [0] "Bart",
    [1] "Hello 2"
]
I, [2016-04-06T17:16:44.656504 #7332]  INFO -- : (0.000050s) SELECT * FROM `people` WHERE `id` = 2
[
    [0] "Homer",
    [1] "Woohoo"
]

====================

I, [2016-04-06T17:16:44.656746 #7332]  INFO -- : (0.000064s) SELECT * FROM `posts`
I, [2016-04-06T17:16:44.657075 #7332]  INFO -- : (0.000078s) SELECT * FROM `people` WHERE (`people`.`id` IN (1, 2))
[
    [0] "Bart",
    [1] "Hello"
]
[
    [0] "Bart",
    [1] "Hello 2"
]
[
    [0] "Homer",
    [1] "Woohoo"
]