On 18/12/2019 14:18, Bernie van't Hof wrote:
>> ... the Answer table will contain numerous data and index fields, from 
>> some/all the contributing tables

> AFAIK no fields will be keyed.

I think so, too.

I think that even a simple extract, of, say, all fields in an indexed 
table (extracting some records, and with no other tables involved) will 
never generate any indices on the answer table.

>> I presume (but I forget) that unfilled data/index fields in PDoxDOS 
>> will contain spaces (for strings), 0.00 (IEEE) for floats, 
>> binary-zeros (NULL) for binary/integer fields, probably 0000 (binary 
>> or IEEE?) also for dates, 0.000 (IEEE) for [Dates+]Times

> AFAIK they will be BLANK

Maybe! If so, that's not good - that would probably result in garbage 
values - for all except string fields! Dang!

(My instinct is that unfilled integer, FP, etc, fields do contain the 
relevant 'zeros' (in PDoxDOS), but I don't recall. I don't know about 
unfilled Dates/Times - "Blanks" would cause chaos, unless all "readers" 
would check for that specific edge-case).