---
type: object
properties:
  agreement_id:
    type: integer
    description: Internal agreement identifier
  related_agreement_id:
    type: integer
    description: Internal related agreement identifier
  relationship:
    description: relationship between the agreements
    type: string
    enum:
      - supersedes
      - is-superseded-by
      - provides_post-cancellation_access_for
      - has-post-cancellation-access-in
      - tracks_demand-driven_acquisitions_for
      - has-demand-driven-acquisitions-in
      - has_backfile_in
      - has_frontfile_in
      - related_to
  notes:
    type:
      - string
      - "null"
additionalProperties: false
required:
  - related_agreement_id
  - relationship
