Thanks Robert.
The ancestor query works great. Read the documentation but i guess it
didn't click
I was looking for a children() like function in the parent.
I don't think I can put it in the same search list.
What if I add a field for type?
class PageIndex(db.Model):
type = db.StringProperty(required=True)
searchlist= db.StringListProperty(required=True)
type can be emails, ipaddresses, usernames
searchlist can be whatever list.
Is this better?
Thanks
Jon
On Sep 1, 3:29 pm, Robert Kluin <[email protected]> wrote:
> Hi Jon,
> 1) When you build a query you can specify the ancestor.
> PageIndex.all(keys_only=True).ancestor(thepage)
> http://code.google.com/appengine/docs/python/datastore/queryclass.htm...
>
> 2) I would not add multiple list properties to the same model. I
> would also probably not make different kinds in this case.
> Personally, depending on exactly how you will need to query and
> maintain the data, I would either just put each field in the same
> "search" list or make a PageIndex entity for each type.
>
> Robert
>
>
>
> On Wed, Sep 1, 2010 at 02:39, ogterran <[email protected]> wrote:
> > Couple more questions
> > 1. If I have the parent entity, how do get all the child entities?
> > 2. If I have more fan out lists, so usernames is one, but now i have
> > emails and ipaddresses
> > is it more efficient to create different entity kinds or just add
> > another list to PageIndex?
> > i.e.
> > class PageIndex(db.Model):
> > usernames = db.StringListProperty(required=True)
> > emails = db.StringListProperty(required=True)
> > ipaddreses= db.StringListProperty(required=True)
>
> > or
>
> > class PageIndex(db.Model):
> > usernames = db.StringListProperty(required=True)
> > class PageEmailIndex(db.Model):
> > emails = db.StringListProperty(required=True)
> > class PageIpAddressIndex(db.Model):
> > ipaddreses= db.StringListProperty(required=True)
>
> > Thanks
> > Jon
>
> > On Aug 31, 11:19 pm, ogterran <[email protected]> wrote:
> >> Thanks guys for all the responses.
> >> I checked out Brett's presentation and he talks about this exact issue
> >> on how to optimize using list properties
>
> >> So following the Brett's presentation, create 2 entitiy kinds.
> >> Page and PageIndex where Page is the parent of PageIndex (specify
> >> parent in PageIndex constructor)
>
> >> class Page(db.Model):
> >> pagekey= db.StringProperty(required=True)
>
> >> class PageIndex(db.Model):
> >> usernames = db.StringListProperty(required=True)
>
> >> indexes = db.GqlQuery("SELECT __key__ FROM MessageIndex "
> >> "WHERE usernames = :1", username)
> >> keys = [k.parent() for k in indexes]
> >> pages = db.get(keys)
>
> >> Since we are querying by key, it is 10x faster, and no unnecessary
> >> serialization.
> >> We can fan out by adding multiple PageIndex, if reaches 5000 max.
>
> >> Is this about right?
>
> >> Thanks
> >> Jon
>
> >> On Aug 31, 9:34 am, Jeff Schwartz <[email protected]> wrote:
>
> >> > A list property's size is limited to 5000.
>
> >> > If you only want to know if a user has visited a page, you can use the
> >> > first
> >> > model & query it returning only keys to avoid list serialization issues.
> >> > In
> >> > addition, key only queries are very fast.
>
> >> > Additionally, if your Page model's key had a string name that was the
> >> > pagecode then you could even use the key to identify the page. In other
> >> > words, you'd be materializing the view in the key of the model. This
> >> > would
> >> > eliminate the need to serialize the entity entirely when it is used for
> >> > lookup.
>
> >> > Writing out the entity after having updated its list property is another
> >> > story all together as writes are subject to fail due to contention. To
> >> > reduce the odds of contention you can shard your model by a factor of 10
> >> > or
> >> > 20 to reduce but not eliminate the possibility of contention.
>
> >> > There are a number of Google IO videos on YouTube that you can watch
> >> > which
> >> > cover these techniques.
>
> >> > Jeff
>
> >> > On Tue, Aug 31, 2010 at 5:22 AM, ogterran <[email protected]> wrote:
> >> > > Hi,
>
> >> > > I have a choice to store the data two ways. Which way is more
> >> > > efficient when querying in BigTable?
>
> >> > > First way:
> >> > > class Page(db.Model):
> >> > > pagekey= db.StringProperty(required=True)
> >> > > usernames = db.StringListProperty(required=True)
>
> >> > > So all the users who visits the page, will be added to the username
> >> > > list
>
> >> > > Second way:
>
> >> > > class Page(db.Model):
> >> > > pagekey= db.StringProperty(required=True)
> >> > > username = db.StringProperty(required=True)
> >> > > All the users who visits the page will have its own row
>
> >> > > The query will be with both username and pagekey.
> >> > > There can be a lot of users.
> >> > > Is there a limit on theStringListsize?
> >> > > what are the advantages of each methods of storing data?
>
> >> > > Thanks
> >> > > Jon
>
> >> > > --
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>
> >> > --
> >> > --
> >> > Jeff
>
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