Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
"Tweetclone" Twitter clone using Sequel (database schema taken from "Cloning Internet Applications with Ruby")
# CREATE DATABASE tweetclone WITH ENCODING 'UTF-8'
require 'sequel'
require 'logger'
# CONNECTION ================================
DB = Sequel.connect(ENV['DATABASE_URL'] ||'postgres://postgres:password@localhost/tweetclone')
# Logging SQL Queries
DB.loggers << Logger.new($stdout)
# TABLES ===================================
Sequel.inflections do |inflect|
inflect.irregular 'status', 'statuses'
end
DB.create_table? :users do
String :nickname, :size => 255, :primary_key => true
String :email, :size => 255, :null => false
String :formatted_name, :size => 255, :null => false
String :provider, :size => 255, :null => false
String :identifier, :size => 255, :null => false
String :phote_url, :size => 255, :null => false
String :location, :size => 255, :null => false
String :description, :size => 255, :null => false
end
DB.create_table? :statuses do
primary_key :id
foreign_key :recipient, :users, :key => :nickname, :type => String,
:on_update => :cascade, :on_delete => :set_null
foreign_key :owner, :users, :key => :nickname, :type => String,
:on_update => :cascade, :on_delete => :cascade
String :text, :size => 140, :null => false
DateTime :created_at, :null => false
end
DB.create_table? :relationships do
foreign_key :user_id, :users, :key => :nickname, :type => String,
:on_update => :cascade, :on_delete => :cascade
foreign_key :follower_id, :users, :key => :nickname, :type => String,
:on_update => :cascade, :on_delete => :cascade
primary_key [:user_id, :follower_id]
end
DB.create_table? :mentions do
foreign_key :user_id, :users, :key => :nickname, :type => String,
:on_update => :cascade, :on_delete => :cascade
foreign_key :status_id, :statuses, :key => :id,
:on_update => :cascade, :on_delete => :cascade
primary_key [:user_id, :status_id]
end
# ASSOCIATIONS ===============================
class User < Sequel::Model
one_to_many :statuses
one_to_many :direct_messages, :class => :Status
many_to_many :friends # Friendship association: A follows B and B follows A
many_to_many :followers,
:class => self, :join_table => :relationships,
:left_key => :user_id, :right_key => :follower_id
many_to_many :follows,
:class => self, :join_table => :relationships,
:right_key => :user_id, :left_key => :follower_id
many_to_many :mentions,
:class => :Status, :join_table => :mentions,
:left_key => :user_id, :right_key => :status_id
many_to_many :mentioned_statuses,
:class => :Status, :join_table => :mentions,
:left_key => :status_id, :right_key => :user_id
end
User.unrestrict_primary_key
class Status < Sequel::Model
many_to_one :recipient, :class => :User
many_to_one :user
many_to_many :mentions, :class => :User, :join_table => :mentions,
:left_key => :status_id, :right_key => :user_id
many_to_many :mentioned_users, :class => :User, :join_table => :mentions,
:left_key => :user_id, :right_key => :status_id
def after_create
self.created_at ||= Time.now
super
end
end
user = User.find(:nickname => "me") || User.create(:nickname => "me")
p user.followers
# SELECT "users".* FROM "users"
# INNER JOIN "relationships"
# ON (("relationships"."follower_id" = "users"."nickname")
# AND ("relationships"."user_id" = 'me')) # why not use 'WHERE' here?
p user.follows
# SELECT "users".* FROM "users"
# INNER JOIN "relationships"
# ON (("relationships"."user_id" = "users"."nickname")
# AND ("relationships"."follower_id" = 'me'))
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment