On Tue, Sep 15, 2009 at 7:33 PM, Tomi Korhonen <[email protected]>wrote:

>
> Hi guys,
>
> I just started learning app engine by developing a small application.
> I am facing following problem:
>
> 1) I have following model
> class Contact(db.Model):
>  name = db.StringProperty()
>  type = db.StringProperty()
>
> class PhoneNumber(db.Model):
>  contact = db.ReferenceProperty(Contact,
>                                 collection_name='phone_numbers')
>  phone_type = db.StringProperty()
>  number = db.PhoneNumberProperty()
>
> 2) I need to fetch all contacts that are type 'A' and those contacts
> should only contain phone numbers that have phone_type 'B' or 'C'
>

The best way to do this is to denormalize: Add "phone_types =
StringListProperty()" to the Contact entity, and populate it with the list
of types that their phone numbers have.


> 3) I have no idea how to solve this :) (One solution would be fetch
> contacts and filter out "wrong" phone_types at application level, but
> I think that is not best way to solve this)
>

This depends on how many you need to fetch, and what percentage you expect
to be filtered out.

-Nick Johnson


>
> Thanks in advance,
> Tomi
>
> >
>


-- 
Nick Johnson, Developer Programs Engineer, App Engine
Google Ireland Ltd. :: Registered in Dublin, Ireland, Registration Number:
368047

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