Rails validate uniqueness of date ranges

Question

I have an application that involves absence records for employees.

I need to ensure that the start and end dates for each record don\'t overlap.

So for example,

Answer 1

I use these:

  scope :overlaps, ->(start_date, end_date) do
    where "(DATEDIFF(start_date, ?) * DATEDIFF(?, end_date)) >= 0", end_date, start_date
  end

  def overlaps?
    overlaps.exists?
  end

  # Others are models to be compared with your current model
  # you can get these with a where for example
  def overlaps
    siblings.overlaps start_date, end_date
  end

  validate :not_overlap

  def not_overlap
    errors.add(:key, 'message') if overlaps?
  end

  # -1 is when you have a nil id, so you will get all persisted user absences
  # I think -1 could be omitted, but did not work for me, as far as I remember
  def siblings
    user.absences.where('id != ?', id || -1)
  end

Source: https://makandracards.com/makandra/984-test-if-two-date-ranges-overlap-in-ruby-or-rails