Determines whether an UPDATE writes NULL values as NULL, or removes them.
By default the driver will use NULL values provided in an UPDATE statement and set the field in Couchbase to NULL.
If this option is disabled SQL NULL values in an UPDATE will cause the driver to mark the field as MISSING. This removes the field from the object containing it, or if the field is contained in an array (per FlattenArrays) then that element is set to NULL.
This option should be used with care as the driver may not detect that the field exists if it is removed from enough documents within a bucket.