hi @Ake, the idea of update at the moment: replace the existing data with the new data from the input file.
As you describe - this is quite destructive.
The idea behind it might be something like:
One cannot guarantee that existing values in additional columns match the newly imported data - so better delete them. Hm, for columns with formulas, I don't see any reason why such columns should be deleted.
Much better than the Update Script:
dt = Current Data Table();
dtnew = dt << Run Script( "Source" );
dt << Select All Rows << Delete Rows;
dt << Concatenate( dtnew, Append to first table );
Close( dtnew, NoSave );
It will still delete manually added values, but it keeps formula columns : )
The drawback: it relies on the source script - which is also very fragile :Update & Concatenate: source script collision .
Alternatively, you could have a look at Join, Concat and Update .