验证一对多关联中的唯一性

Question

我有一个专辑模型和Track模型。我想确保他们所属专辑中每首曲目的名称是唯一的。我尝试在Track模型中使用此验证

validates :name, presence: true, uniqueness: true, scope: :album_id

但得到错误：Unknown validator: 'ScopeValidator'

我做错了什么？

class Album < ActiveRecord::Base
    has_many :tracks

    accepts_nested_attributes_for :tracks, :reject_if => :all_blank, :allow_destroy => true

    validates :name, presence: true, uniqueness: true
end

class Track < ActiveRecord::Base    
  belongs_to :album

  validates :name, presence: true, uniqueness: true, scope: :album_id
end

Answer 1

您需要确定唯一性的范围，而不是将其作为单独的参数。

class Track < ActiveRecord::Base    
  belongs_to :album

  validates :name, presence: true, uniqueness: { scope: :album_id }
end