|Date:||Wed, 18 Dec 2019 13:52:17 +0000
|From:||Michael Kennedy <Info@KennedySoftware.ie>
Don't read the following! ;-)
On 18/12/2019 06:39, Bernie van't Hof wrote:
> Well I'm not much better!
> Just about sorted crosstab (at least conceptually) and made an awkward
> discovery in the process.
> CREATE TABLE `Answer` AS SELECT ... seems innocuous enough.
> But I hadn't noticed before that it brings NULL/NOTNULL settings from
> SELECT columns into the new table. The benefits are obvious, but is
> different to pdox which generates the Answer table unkeyed. Ho Hum :(
"Unkeyed" sounds correct to me - we're emulating a PDoxDOS app! Surely
(?) the Answer table will contain numerous data and index fields, from
some/all the contributing tables, and maybe a few calculated fields,
summary fields, counts, etc, but presumably there's no way of knowing
what would be a suitable primary index on that answer table, nor what
sec-indices would be useful?
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, etc, and I expect unfilled
SQL fields would contain the same values? I wonder would empty
Dates/Times be different?
If I can do a bit of digging for you, let me know.