On Feb 15, 2008, at 9:56 AM, Balázs Klein wrote:
given that answers for a questionnaire are stored as a
batch
Not in our setup - for all sorts of reasons (preserving responses
on a connection failure or restart, monitoring response latency in
real time, creating adaptive/branching questionnaires) we send each
response separately.
people running reports on will be the ones to notice, i.e. at
retrieval time.
I am not sure - different responses are aggregated into different
attributes in different ways - those properties need to be
retrieved during scoring/report generation, so being able to create
a join directly on a response is a good thing for me. But report
generation - in our case it must be a DTP quality PDF - is such a
beast anyway that db times dwarf compared to pdf generation.
The problem comes when I need to present the responses themselves
in a human-friendly way - as an export or display or report. Do you
think there is a way to ensure that the order of the values in the
array below is the same for each person?
tbl(eID, aID, value)
Select eID, array_accum(value) from
(
(Select Distinct eID from tbl) e
CROSS JOIN
(Select Distinct aID from tbl) a
) ea
LEFT OUTER JOIN
tbl USING (eID, aID)
GROUP BY eID
The only way to ever guarantee a particular order is via an ORDER BY
clause.
Erik Jones
DBA | Emma®
erik@xxxxxxxxxx
800.595.4401 or 615.292.5888
615.292.0777 (fax)
Emma helps organizations everywhere communicate & market in style.
Visit us online at http://www.myemma.com
---------------------------(end of broadcast)---------------------------
TIP 6: explain analyze is your friend
