Suppose I have:
class Author
has_many :books
class Book
belongs_to :author
validates :name, :presence => true, :uniqueness => true
I want to change this so that the name of the book is only unique within the scope of the author, i.e. no author has two books with the same name, but two authors could have a book with the same name. Is this possible?
It's very possible and quite easy:
validates :name, :presence => true, :uniqueness => {scope: :author}
validates :name, :presence => true, :uniqueness => {:scope => :author_id}
Related
When updating car info, the validation process fails because I have validates_uniqueness_of :number
class Car < ActiveRecord::Base
validates :number,numericality: true, length: {is: 7 }
validates :number, :name, presence:true
validates_uniqueness_of :number, :message => "מספר רכב זה קיים במערבת"
belongs_to :owner
has_many :visits
end
I need validation to pass, if the original value was not changed, validation on_create would not help since I still need validation when updating.
Any help would be really appreciated.
This will work for you :
validates :number, :uniqueness => {:scope => :number}, :message => "מספר רכב זה קיים במערבת"
OR
validates_uniqueness_of :number, :message => "מספר רכב זה קיים במערבת", :scope => :number
I have the following model in rails (simplified):
class Phone < ActiveRecord::Base
include ActiveModel::Validations
belongs_to :user
belongs_to :brand
attr_readonly :user, :brand
attr_accessible :model, :phone_number
validates :user, :presence => true
validates :brand, :presence => true
validates :model, :presence => true
validates :phone_number, :presence => true
end
According to the documentation, attr_readonly should allow attributes to be set at creation, but not at update.
However, when I do this:
Phone.create(:user => <existing_user>, :brand => <existing_brand>, :model => "Galaxy", :phone_number => "555-433-5678")
I get this error:
Can't mass-assign protected attributes user, brand
What am I missing?
If you want to assign a user and a brand association like that, you must define them as being accessible attributes:
attr_accessible :user, :brand
Otherwise, you can assign them like this:
Model.create({:user => user, :brand => brand }, :without_protection => true)
I have products and brands
products model:
class Product < ActiveRecord::Base
attr_accessible :brand_id, :title
belongs_to :brand
validates :title, :presence => true
validates :brand, :presence => {:message => 'The brand no exists'}
end
and the brands model
class Brand < ActiveRecord::Base
attr_accessible :name
validates :name, :presence => true
has_many :products, :dependent => :destroy
end
I want to validate if exist a product with a name in this brand.
I mean I could have 2 products with the same name in different brands but not in the same brand.
You could use the uniqueness validation with a scope:
validates :name, :uniqueness => { :scope => :brand_id }
Note that you have to specify :brand_id instead of :brand, because the validation can't be made on the relation.
If you don't know it, I suggest you to read the Active Record Validations and Callbacks guide.
NB: the syntax {:foo => 'bar'} is replaced (since Ruby 1.9.2) with {foo: 'bar'}.
I have something like:
class Event
validates :name, :prescence => true
belongs_to :parent, class => "Event", foreign_key => "parent_id"
has_many :children, class => "Event"
I want to change it so that a name is only required when an event doesn't have a parent.
validates :name, :presence => true, :if => Proc.new {|event| event.parent.blank? }
should work fine. Please read docs for further information.
I am trying to write a unit testing for a User model in Ruby on Rails. I am using authlogic and need to check that the first_name and last_name of the user model attributes are not the same when the user is registering.
This is my user model:
class User < ActiveRecord::Base
acts_as_authentic do |c|
c.login_field= :username
end
has_many :memberships, :class_name => "Project::Membership"
has_many :projects, :through => :memberships
has_one :profile
validates :email, :presence => true, :uniqueness => true
validates :username, :presence => true, :uniqueness => true
validates :first_name,:presence => true
validates:last_name, :presence => true
validates :title, :presence => true
validates :password, :presence => true
validates :password_confirmation, :presence => true
validates :gender, :presence => true
# Custom validator
validates :first_name, :last_name, :different_names => true
As you can see, I tried to create a custom validator creating a new file in /lib/different_names_validator.rb with a class called DifferntNamesValidator, but couldn't get it, as I got the following error: Unknown validator: 'different_names' (ArgumentError)
Thanks in advance!
Hi Try to include this module in your model