def assert_valid_properties
      repository_name = self.repository_name
      if properties(repository_name).empty? &&
        !relationships(repository_name).any? { |relationship| relationship.kind_of?(Associations::ManyToOne::Relationship) }
        raise IncompleteModelError, "#{name} must have at least one property or many to one relationship in #{repository_name} to be valid"
      end
    end
def assert_valid_properties
      repository_name = self.repository_name
      if properties(repository_name).empty? &&
        !relationships(repository_name).any? { |relationship| relationship.kind_of?(Associations::ManyToOne::Relationship) }
        raise IncompleteModelError, "#{name} must have at least one property or many to one relationship in #{repository_name} to be valid"
      end
    end
Test if the model has properties

 A model may also be valid if it has at least one m:1 relationships which
 will add inferred foreign key properties.

 @return [undefined]

 @raise [IncompleteModelError]
   raised if the model has no properties

 @api private