in this case, basic changes made to the interchange format of the database are transmitted to the vehicle. such changes are represented in transactional form consisting of "additions", "deletions" and "replacements". these changes are applied to the existing onboard database in interchange format. the interchange format for the onboard database could either be stored separately or generated as needed by “decompiling” the run-time format. the combined database is then compiled, which involves assigning ids and applying indices.