An incremental update can be carried out using the following procedure:
- Select records from the previous release of Postcodes data where the POSTCODE values match those of the Incremental table and the CHANGE_TYPE = D or U (Deletion or Update respectively)
- Delete the selected records from the old Postcodes data.
- Select from the new Postcodes incremental table where the CHANGE_TYPE = I or U (Insertion or Update respectively).
- Append the selected records to the old Postcodes data. The resulting table will contain the updates for the current version of Postcodes, but will retain the old table structure.