The best way to validate the presence of a belongs_to association?

[robs]

For example:

class Person
include DataMapper::Resource

property :id, Integer, :serial => true
property :first_name, String, :nullable => false
property :last_name, String

has n :posts
end

class Post
include DataMapper::Resource

property :id, Integer, :serial => true
property :title, String, :nullable => false
property :body, Text

belongs_to :author, :class_name => "Person"
end

What would be the best way to validate the presence of an author when
a post is saved? I noticed that the documentation says that some
validations are automatically inferred (e.g., if :nullable => false
or :length is specified). Is there any way to include this validation
in the belongs_to method call? If not, what would anyone suggest?

Thanks!

[Chris Van Pelt]

validates_present :author

[robs]

That was embarrassingly easy. Thank you!

[Chris Van Pelt]

No problem :)