The document discusses Rails model validations which ensure only valid objects are persisted to the database. It describes different validation methods like presence, length, numericality, and uniqueness that can be applied to model attributes. These validations are triggered during create, save, update, and update_attributes and allow specifying validation criteria like minimum or maximum length, numeric comparisons, and unique values within a scoped context.

1. Validações!
http://edgeguides.rubyonrails.org/
active_record_validations.html

2. Validações Rails
•
Configurações no modelo
•
Garantem que somente objetos válidos
sejam persistidos
•
Métodos que disparam
•
create
•
save
•
update
•
update_attributes

3. Obrigatório
class Person < ActiveRecord::Base
validates :name, presence: true
validates_presence_of :idade
end

4. Tamanho
class Person < ActiveRecord::Base
validates :name, length: { minimum: 2 }
validates :bio, length: { maximum: 500 }
validates :password, length: { in: 6..20 }
validates :registration_number, length: { is: 6 }
end

5. Tamanho
class Essay < ActiveRecord::Base
validates :content, length: {
minimum: 300,
maximum: 400,
too_short: "minimo %{count} caracteres",
too_long: "maximo %{count} caracteres"
}
end

6. Numéricos
class Player < ActiveRecord::Base
validates :points, numericality: true
validates :games_played, numericality: { only_integer: true }
end

7. Numéricos
:greater_than
:equal_to
:greater_than_or_equal_to
:odd
:less_than
:even
:less_than_or_equal_to
!
!

8. Unicidade
class Account < ActiveRecord::Base
validates :email, uniqueness: true
end

9. Unicidade
class Holiday < ActiveRecord::Base
validates :name, uniqueness: { scope: :year,
message: "should happen once per year" }
end

10. Unicidade
class Person < ActiveRecord::Base
validates :name, uniqueness: { case_sensitive: false }
end