Limit number of objects in has_many association

ruby-on-rails

Solution

In my case, it was sufficient to use `validates_length_of`:

class Album
  has_many :photos
  validates_length_of :photos, maximum: 10
end

class Photo
  belongs_to :album
  validates_associated :album
end

Problem

I have an album which has_many photos. A counter_cache setup updates the photos_count column in the album table. How do I limit the number of photos for an album?

Original source

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