The document discusses an upcoming Medellín.rb meetup focused on ActiveRecord internals. The schedule includes introducing the Active Record pattern, an overview of ActiveRecord as implemented in Rails, and a code kata exercise to implement basic ActiveRecord methods like .first, .all, and .find_by. It provides background readings and links on architectural patterns, Active Record pattern, and the Rails ActiveRecord basics guide.

1. Medellín.rb
ActiveRecord Internals
@RubyMedellin
http://medellinrb.org

2. Schedule
- Say Hi
- Active Record Pattern
- ActiveRecord (Rails)
- Yummy yummy
- Code Kata
@RubyMedellin
http://medellinrb.org

3. PEAA
http://www.amazon.com/Patterns-Enterprise-Application-Architecture-
Martin/dp/0321127420

4. GoF
http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612/

5. Ruby Patterns
http://www.amazon.com/Design-Patterns-Ruby-Russ-Olsen/dp/0321490452/

6. Active Record Pattern
An object that wraps a row in a
database table or view,
encapsulates the database
access, and adds domain logic
on that data.
http://www.martinfowler.com/eaaCatalog/activeRecord.html

7. ActiveRecord (Rails)
Active Record facilitates the creation and
use of business objects whose data
requires persistent storage to a database.
It is an implementation of the Active
Record pattern which itself is a description
of an Object Relational Mapping system.
http://guides.rubyonrails.org/active_record_basics.html

8. ActiveRecord (Rails)
- ActiveModel
- Migrations
- Adapters
- Validations
- Callbacks
- etc
http://guides.rubyonrails.org/active_record_basics.html

9. ActiveRecord (Rails)
class Product < ActiveRecord::Base
# ...
end
Product.first
Product.where(name: ‘LCD TV’)
http://guides.rubyonrails.org
class CreateProducts <
ActiveRecord::Migration
def change
create_table :products do |t|
t.string :name
t.text :description
t.timestamps null: false
end
end
end

10. DEMO
Code will be uploaded to: https://github.com/medellinrb/activerecord-internals

11. Yummy yummy

12. Code Kata

13. Code Kata
Kata (型 or 形 literally: "form"?
), a Japanese word, are the
detailed choreographed patterns of movements practised
either solo or in pairs.
A code kata is an exercise in programming which helps a
programmer hone their skills through practice and
repetition.
http://en.wikipedia.org/wiki/Kata_(programming) - http://en.wikipedia.org/wiki/Kata

14. Today’s Kata
Implement:
SomeModel.first
SomeModel.all
SomeModel.count
SomeModel.find_by_name(‘given name’)
SomeModel.find_by_whateverattribute(‘xxx’)
SomeModel.where(attr: ‘value’)
Improve multiple DB adapters
Improve setup/teardown on tests

15. Thanks <3
Medellín.rb
@RubyMedellin
http://medellinrb.org