+1. Nick Johnson's DerivedProperty has proved invaluable during the course
of my development on App Engine.
Jon, in your example, this is how you could implement it using
DerivedProperty:
----------------------
*from aetycoon import DerivedProperty*
class Message(db.Model):
text= db.StringProperty(required=True) # text of the message
likes= db.StringListProperty() #usernames that liked the message
* @DerivedProperty*
* def num_likes(self):*
* return self.likes and len(likes) or 0*
----------------------
Then to get the top 10 liked messages:
----------------------
messages = Message.all().order('-num_likes').fetch(10)
----------------------
Nick
On 2 March 2011 22:59, djidjadji <[email protected]> wrote:
> You can use the DerivedProperty from the aetycoon lib written by Nick
> Johnson (search his blog).
> During a put it will update the property no need to perform the count
> yourself.
>
> 2011/3/1 ogterran <[email protected]>:
> > Thanks guys. I'll add another IntegerProperty to increment the count
>
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