Rails 3验证,多个字段

Question

有4个字段(α,β,γ,δ),它们中的至少1必须有一个值,即不是nil /空/空.如何创建验证以确保这一点？

Answer 1

validate :something_must_be_set

def something_must_be_set
  unless alpha || beta || gamma || delta
    errors.add(:base, "Alpha, Beta, Gamma or Delta must be present.")
  end
end