[QGIS-Developer] Duplicate Features

[Richard Duivenvoorde]

On 31-10-17 11:44, Matthias Kuhn wrote:
> Hi list,
> 
> For QGIS 3.0 we have created a new feature "duplicate features", that
> allows duplicating features with associated children whenever a relation
> is defined as "composition" (https://github.com/qgis/QGIS/pull/5448).
> 
> There is a new configuration option in place as well as core
> functionality with unit tests.
> 
> However, this code is currently nowhere triggered inside QGIS. We have
> written custom python code for a feature action to make it work for the
> client who ordered this. Still, it is unfortunate to have a
> configuration option which has no effect without writing custom python code.
> 
> We could add this code as default action, given that this is opt-in and
> the underlying code is tested by unit tests I would feel comfortable to
> bring this in at the current state and treat this as a GUI fix.
> 
> If others feel uncomfortable, please say so and we can point the users
> towards the documentation and mention the python code for the action for
> copy pasting there, or mark the configuration option as experimental.

Hi Matthias,

It's always nice to see new 'features' :-)

But this one I think needs very clear proper documentation, can you or
the dev who wrote it please write some good documentation? Because this
option is not a trivial one to understand for an average user. Otherwise
it will take document writers time to find out. Given it is paid code,
you probably also offered to write the docs as part of the job isn't it ;-)

The dialog I see in the Pull Request definitly need a help button
pointing to some Documentation page about relations (and this 'copy be
reference/value' stuff...).

I was also wondering what happens if you delete one of those duplicate(s)?
IF you also copy the related record, what happens with that record when
you delete the referencing one (the referenced one should be deleted too?)
Or how do you clean up those copies (aka how do you manage integrity?).

Working with 'duplicates' is always tricky, I've had several problems of
people wondering why they lost features in both layers, after
'duplicating' a layer, and deleting features in one of them...

Regards,

Richard Duivenvoorde