Summary:
The import dialog now has an option to 'Update existing records',
which when checked will allow for selection of 1 or more fields
to match source and destination tables on.
If all fields match, then the matched record in the
destination table will be merged with the incoming record
from the source table. This means the incoming values will
replace the destination table values, unless the incoming
values are blank.
Additional merge strategies are implemented in the data
engine, but the import dialog only uses one of the
strategies currently. The others can be exposed in the UI
in the future, and tweak the behavior of how source
and destination values should be merged in different contexts,
such as when blank values exist.
Test Plan: Python and browser tests.
Reviewers: paulfitz
Reviewed By: paulfitz
Subscribers: alexmojaki
Differential Revision: https://phab.getgrist.com/D3020
Summary: This moves enough server material into core to run a home server. The data engine is not yet incorporated (though in manual testing it works when ported).
Test Plan: existing tests pass
Reviewers: dsagal
Reviewed By: dsagal
Differential Revision: https://phab.getgrist.com/D2552
