[digiKam-users] Sharing Database/Collections

[Martin Burnicki]

Sveinn í Felli wrote:
> Þann 19.9.2019 08:49, skrifaði Martin Burnicki:
>> Andrey Goreev wrote:
>>> I do not think digiKam can do that...
>>
>> Shouldn't this work if the collection is in a cloud folder like
>> Nextcloud (or Dropbox, FWIW)?
>>
>> If you make changes to photo or an album (i.e. just the file or photo)
>> on one machine then the changes are synchronized to all machines that
>> share these folders, and if you start DK next time it will detect the
>> changes and update the local database accordingly.
>>
>> But of course this is only going to work if you write tags and other
>> metadata to the image file or a sidecar file.
>>
>> If you have configured DK to *not* write metadata (tags etc.) to the
>> files but keep them only in the DB you'd have to synchronize the
>> database in a consistent way, which can be much harder.
>>
> 
> IMHO it could be instructive to set up Nextcloud on a NAS over a LAN,
> and try out how Digikam reacts to such synchronization - both databases
> and image files. Probably I will test this kind of a setup, but not
> until late October when time permits.

Hm, this sounds as if you intend to work directly on the NAS, across the
LAN. This won't work when the NAS is not accessible, e.g. from a laptop
that has no network connection.

My suggestion would be to have a local copy of the collection on the
laptop, so you can edit images, and reorder images and albums locally on
your laptop, as required.

When the laptop has a network connection again, the edited/moved files
and folders would be first synchronized to the cloud, and then to other
machines (e.g. PCs) that share the same collection folders.

If you start DK on one of the other machines it detects the changes and
updates its DB. This also works in the reverse direction: if you make
changes on the PC then the changes will be synchronized to the laptop
when the laptop is powered up next time with a network connection.

> Nextcloud/OwnCloud has fine-grained access-controls for users/groups and
> sharing, and has pretty advanced mechanisms for resolving conflicts in
> case of simultaneous edits.
> 
> I presume that if using a synchronized database one would have to share
> _all_ the files in each local collection _and_ the paths would have to
> be the same on all devices, right?

Right. That's what I meant, see above. But of course you could organize
your collection in a way that only specific albums/folders are
synchronized via the cloud.

However, from my understanding, synchronizing the DB between the machine
will only work without problems if you use sqlite as DB, and if all
machines run the same DK version, i.e. expect the same DB layout.

If your DB uses mysql then I'd expect that you run into huge problems if
you try to synchronized the DB by just synchronizing its files.

If you keep the databases only locally then there should be no problems
at all, if you only synchronize files and folders, even if you run
different version of DK on different machines. But, as said earlier,
this works for metadata (tags etc.) only if they are written into the
image or sidecar files.

Martin