ActiveRecord
Basics
ORM in Rails
Object
+
Relational
Mapping
ORM
ActiveRecord connects classes to relational database tables.
'M' in MVC
Model
The layer of the system responsible for representing business data and logic.
Associations
Associations
- belongs_to
- has_one
- has_many
- has_many :through
- has_one :through
- has_and_belongs_to_many
Validations
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."
- Martin Fowler