First of all, please remember that GAE/database is an Object-database,
not a Relational-database. You can design your database with
relations, but you will likely hit a roadblock later if you heavily
rely on relations (because of the lack of JOIN and the performance
problem of nested queries).
If
I'd add "reference_count" property (IntegerProperty(default=0)) to
Photo entity, and increment it each time a reference happens. Then,
call Photo.all().order("-reference_count").fetch(100) to get the top
100 most referenced photos.
A few additional notes:
1. If you need an accurate reference count
Satoshi made very good suggestions. Also, remember that because there
are no JOINs or efficient sub-queries, you need to denormalize your
data a lot too. So if you want something like a list of photographs
with artist name you may want to store the artist's name on the Photo
entity too (along wit
Hi Satoshi,
thanks for your reply, it really helped.
In fact I just read this artile:
http://code.google.com/appengine/articles/modeling.html
and have started implementing based on it.
Still wondering a couple of things, though...
for instance, in my app I have another class called Collage.
A coll
The datastore has no aggregation functions. To get that type of
summary data you will want to precompute it.
Robert
On Wed, Jan 6, 2010 at 7:15 PM, Daniel Aguilar wrote:
> Hi Satoshi,
>
> thanks for your reply, it really helped.
> In fact I just read this artile:
> http://code.google.com
Hi again,
thanks a lot for your answers.
So it looks like developing for GAE is quite a different paradigm...
>From your answers i understand that:
1. I should precompute and store all aggregated data I might need
2. Changes to my database are NOT immediate (hence I can't expect accuracy)
I will
