PyArrow Flight: Empty Strings in pa.Table Converting to NULLs When Reading/Writing to Exasol

Question

I'm reading and writing a table on Exasol using PyArrow Flight. I noticed an issue, where empty strings get converted to NULLs in the flight process. When I write a pa.Table containing a column of ""s to Exasol, the resulting table contains NULLs rather than "". I confirmed the same issue the other way around. When reading the data and explicitly replacing the NULLs to "" in the select query, the resulting pa.Table also contains NULLs, rather than "".

Could this issue be caused by an option set in PyArrow's FlightDescriptor or FlightClient?

Answer 1

See NULL in Exasol:

Exasol does not distinguish between NULL and an empty string ('')