For real you aren't just getting us to do your homework? This is a very
common question in Comp Sci Classes.
Just in case this is just logic in a mish mash of PHP, python, and java
syntax J
$RandomNumberOne = RND(1,100000000000000) // we have lots of questions
Array($AnsweredQustions) = Query
While ( $RandomNumberOne iscontainedin $AnsweredQustions )
{
$RandomNumberOne++
}
Fetch_QuestionByID($RandomNumberOne)
///////////////
If you need it to be more random take the random number and pick a number
half way between it and the max rather than just incrementing.
From: google-appengine@googlegroups.com
[mailto:google-appengine@googlegroups.com] On Behalf Of DurhamG
Sent: Thursday, January 12, 2012 7:36 PM
To: google-appengine@googlegroups.com
Subject: [google-appengine] Data schema for showing a user 5 random
questions they haven't already answered?
I've been trying to figure this one out for a few hours now:
I have an ever growing table of questions, and an ever growing table of
users. For a given user, I would like to query for 5 random questions that
they have not already answered. What kind of model schema would allow this?
I've seen how to query for N (semi)random entities
<http://stackoverflow.com/questions/3002999/fetching-a-random-record-from-th
e-google-app-engine-datastore> (which uses a > query filter), and I've seen
the presentation
<http://www.google.com/events/io/2009/sessions/BuildingScalableComplexApps.h
tml> on how to do microblogging style schemas (which uses = on lists as a
query filter), which together might allow me to query for '5 random
questions the user has already answered'. To do the opposite though would
require > and != on different properties which isn't allowed.
The best I can come up with so far is to keep a list of the answered
questions on the user entity, then query for batches of random questions
until I find 5 which aren't in their list. This assumes the number of
questions answered by a single user remains under 5000 (the list size limit
if I recall) and that there are more unanswered questions than answered ones
for any given user (so that I don't have to pull too many batches in looking
for questions). These limitations might be reasonable, but this approach
still seems less than optimal.
Any ideas on how to accomplish this?
Someone asked this question a couple years ago with no response
<http://groups.google.com/group/google-appengine/browse_thread/thread/83012c
2aab80fedf/c6b08354b23dc7e9?lnk=gst&q=schema+random+suggestions#c6b08354b23d
c7e9> , so I'm hoping some changes have occurred in the mean time to make
this possible.
Thanks!
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