In principle, for larger and/or frequently changing catalogues (or article states), we offer to transfer individual articles via so-called DELTA updates.
The structure of the file should correspond exactly to the structure of the normal (FULL) catalogue file. If deletions are also to be mapped here, there should be a column called “deleted”, which should be filled with “1” in the corresponding lines.
If the DELTA is to be fetched via an http link, we recommend keeping exactly one DELTA file, which will be supplemented until the next FULL update is created.
If an (s)FTP server is used for exchange, several DELTA files (e.g. per hour or per cycle) can also be created, which you should mark with a timestamp. Ideally, these should be in a separate subfolder called “DELTA”.