Merge when importing

[oleua]

Is your feature request related to a problem? Please describe.

Hi! Please, add the option to merge data with the existing when importing.
I have a case on regular importing data from several different sources (csv/xlsx tables).

Describe the solution you'd like

Currently, the importing function will insert new records each time the import is done. I would like to define the key field, if values are present, the existing record will be updated, otherwise a new record inserted.

Describe alternatives you've considered

I would like to have the procedure to be run both interactively and via cli OCC, eg occ tables:update key=<key field>

Additional context

Of course, occ tables:import function should be added!

[enjeck]

I believe this is being done at #1824, but the "key field" is the ID