Validate the number of has_many items in Ruby on Rails
You can always create a custom validation.
Something like
validate :validate_tags
def validate_tags
errors.add(:tags, "too much") if tags.size > 5
end
I think you can validate with using .reject(&:marked_for_destruction?).length
.
How about this?
class User < ActiveRecord::Base
has_many :groups do
def length
reject(&:marked_for_destruction?).length
end
end
accepts_nested_attributes_for :groups, allow_destroy: true
validates :groups, length: { maximum: 5 }
end
Or this.
class User < ActiveRecord::Base
has_many :groups
accepts_nested_attributes_for :groups, allow_destroy: true
GROUPS_MAX_LENGTH = 5
validate length_of_groups
def length_of_groups
groups_length = 0
if groups.exists?
groups_length = groups.reject(&:marked_for_destruction?).length
end
errors.add(:groups, 'too many') if groups_length > GROUPS_MAX_LENGTH
end
end
Then, you can command.
@user.assign_attributes(params[:user])
@user.valid?
Thank you for reading.
References:
http://homeonrails.com/2012/10/validating-nested-associations-in-rails/ http://qiita.com/asukiaaa/items/4797ce44c3ba7bd7a51f
A better solution has been provided by @SooDesuNe on this SO post
validates :tags, length: { minimum: 1, maximum: 6 }