Great question!
I have a somewhat similar model in my app (it's not articles but the
query is similar), here's how I do it:
I de-normalise the data specifically for this query, that is I have a
kind:
UserComment:
user = db.UserProperty()
last_commented = db.DateTimeProperty()
# de-normalised data from the article model (key, title, slug,
etc).
When the user creates a comment, I add a UserComment if it's the first
comment for the user in this article.
I also add an entity to the job queue model for background processing.
The background worker (triggered by pinging from an external box)
updates UserComment.last_commented for all users that also commented
the article.
It's far from perfect, there's a (slight) delay in update, but
otherwise it works. I'm very interested in how others would implement
this.
Alex
--
www.muspy.com
On Nov 13, 9:50 am, MajorProgamming <[EMAIL PROTECTED]> wrote:
> I was wondering how to approach the following:
>
> Suppose I have three DB Models that look something like this:
>
> MainListOfArticles(db.Model):
> articleText=db.Text
> [...]
>
> CommentsOnArticles(db.Model):
> commentText=db.Text
> articleRef=db.ReferenceProperty(MainListOfArticles)
> userThatWrote=db.UserProperty
> [...]
>
> Users(db.Model):
> userObject=db.UserProperty
> [...]
>
> Now suppose I would like to retreive all articles that the user
> commented on, based on the recency of the latest comment on that
> article. I.e: when a user logs in he gets a decending list of all
> articles *that he commented on* sorted by how recently they were
> commented on (by others).
>
> To put it in other words: To get all articles based on the recency of
> their comments would be easy: simply retrieve the comments sorted by
> order descending. However, I would like a way to specifically retreive
> those that the user commented on.
>
> Another point: I want the solution to scale. Keep in mind that there
> could be an infinite number of articles and users. So storing them in
> an individual entity would not work. There is a 1MB limit per entity
> (that probably squashes many possible solutions).
>
> Thanks for your help,
>
> And if I didn't explain everything correctly, please ask me to clarify
> a point....
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