text: -- policy for warning unencryption volumes
  CREATE SCHEMA unencrypted_volume;
  
  -- `warning` view consisting of unencrypted volumes in use (attached)
  CREATE VIEW unencrypted_volume.warning AS
  SELECT d->>'id'          AS volume_id,
         d->'attachements' AS attachements
  FROM   _volume.volumes
  WHERE  NOT d @> '{"encrypted": true}'::jsonb
  AND    jsonb_array_length(d->'attachments') != 0;
  