pure Ruby DB toolkit

1. Sequel
pure Ruby DB Toolkit

2. http://sequel.rubyforge.org/

3. Ruby Toolbox
• Database Abstraction - Adapters
• DSL - Ruby
• ORM - Models

4. Adapters
• SQLite
• MySQL (2)
• PostgreSQL
• DBI

5. gem install sequel
gem install sqlite3
gem install mysql2

6. Connect to DB
• DB = Sequel.sqlite (in-memory)

7. Connect to DB
• DB = Sequel.sqlite (in-memory)
• DB = Sequel.connect (‘sqlite://test.db’)

8. Connect to DB
• DB = Sequel.sqlite (in-memory)
• DB = Sequel.connect (‘sqlite://test.db’)
• DB = Sequel.connect (‘mysql://...’)
• DB = Sequel.connect (‘postgres://...’)

9. Ruby Toolbox
sequel -E sqlite://test.db

10. Database Object

11. DB - Database Object
• DB.tables
• DB.table_exists?(:items)
• DB.schema(:items)
• DB.add_index :items, :name

12. SQL QUIZ !
Rename table

13. SQL QUIZ !
DB.rename_table
:items , :mono

14. SQL QUIZ !
ALTER TABLE `items`
RENAME TO `mono`

16. DB.run(‘ALTER TABLE ’)
DB.rename_table

17. Dataset Object

18. Unique for Sequel

19. Dataset object
SQL Query
as
Object

20. DB[:items]

21. Immutable
Dataset
Return
Dataset (copy)

22. Chainable
DB[:Items]
SELECT * FROM `items`

23. Chainable
DB[:Items] where(‘price > 10’)
SELECT * FROM `items`
WHERE (price > 100)

24. Chainable
DB[:Items] where(‘price > 10’) order(:name) limit(10)
SELECT * FROM `items`
WHERE (price > 100)
ORDER BY `name` LIMIT 10

25. Two type of returns
Dataset return Dataset’
id name
Dataset return
1 a
2 b
DB[:items].limit(10).all

26. require ‘sequel_core’

27. Model

28. require ‘sequel’
class Item < Sequel::Model
Dataset
end

29. Associations
class Item < Sequel::Model
many_to_one :users
end
class User < Sequel::Model
one_to_many :items
end

30. Associations
ActiveRecord Sequel
belongs_to many_to_one
has_many one_to_many
has_and_belongs_to... many_to_many
has_one one_to_one

31. Other features
• Model validations - validate_*
• Model hooks - before, after
• Migrations
• Transactions

32. Questions?