thanks.
在 2014年7月26日星期六UTC+8上午9时02分35秒，Jay写道：
>
> I just deployed a little test app. It is under quota so I don't think
> appstats is reporting that for me.
>
> However, the important thing to note in this context is that whether I use
> the db api or ndb, it is the same datastore operation ... which is a query
> in this case.
>
> If you still need "proof", I suggest you write your own test application.
> As Vinny suggested, you can post that and there might be some more
> discussion to come from it.
>
> On Friday, July 25, 2014 9:26:27 AM UTC-5, saintthor wrote:
>>
>> how many entities is in your db? how many ops cost for one call?
>>
>> 在 2014年7月25日星期五UTC+8上午8时03分44秒，Jay写道：
>>>
>>> I wrote a simple test app that used both the db and ndb api and deployed
>>> it to app engine. Using appstats I confirmed that both RunQuery when
>>> getting the list of articles.
>>>
>>> On Wednesday, July 23, 2014 8:03:40 PM UTC-5, Jay wrote:
>>>>
>>>> I refer you to line 3865 of __init__ in the ext.db package in the sdk.
>>>> This is on a _ReverseReferenceProperty that gets setup.
>>>> If I have time tomorrow I will write a quick test to demonstrate.
>>>>
>>>> On Wednesday, July 23, 2014 11:11:31 AM UTC-5, saintthor wrote:
>>>>>
>>>>> are you sure?
>>>>>
>>>>> i tested in two apps. the first is using query. when i do a query, the
>>>>> read ops increases about 300. the second is using referenceproperty as
>>>>> above, after 5 times showing, there is no obviously increase.
>>>>>
>>>>> the articles in the second app is much more than the first. so i don't
>>>>> think it run a query.
>>>>>
>>>>> 在 2014年7月22日星期二UTC+8下午11时20分14秒，Jay写道：
>>>>>>
>>>>>> When you use that api in db, it is doing a query underneath the
>>>>>> covers.
>>>>>>
>>>>>> On Monday, July 21, 2014 11:27:08 PM UTC-5, saintthor wrote:
>>>>>>>
>>>>>>> in db, i set such a property in model article:
>>>>>>>
>>>>>>> auth = db.ReferenceProperty( author, collection_name="AuthSet" )
>>>>>>>
>>>>>>>
>>>>>>> and use author.AuthSet to get all articles written by the certain
>>>>>>> author. there is no query. how can i do the same thing in ndb?
>>>>>>>
>>>>>>>
>>>>>>> 在 2014年7月22日星期二UTC+8上午3时55分28秒，Jay写道：
>>>>>>>>
>>>>>>>> Responding to your first post ... that is right. The parent key is
>>>>>>>> part of the entity's key. When you use get_by_id, this is just
>>>>>>>> shorthand
>>>>>>>> for Key('Foo', 99).get().
>>>>>>>> You cannot get an entity by key unless you know the key, the whole
>>>>>>>> key.
>>>>>>>>
>>>>>>>> You say you don't want to query, but your use case ... "give me all
>>>>>>>> articles for user A" ... sounds like a query.
>>>>>>>> articles = Article.query(Article.author == user_key)...
>>>>>>>>
>>>>>>>> If you want to do something like "most recent n articles" then you
>>>>>>>> can store those keys in a 'secondary index' of sorts and use
>>>>>>>> ndb.get_multi()
>>>>>>>>
>>>>>>>> On Monday, July 21, 2014 8:11:20 AM UTC-5, saintthor wrote:
>>>>>>>>>
>>>>>>>>> to query may cost too many ops. i don't query.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 在 2014年7月21日星期一UTC+8下午8时53分29秒，Kaan Soral写道：
>>>>>>>>>>
>>>>>>>>>> Not associated with google, also not an expert on ndb
>>>>>>>>>>
>>>>>>>>>> As far as I know key groups are related with consistency, in my
>>>>>>>>>> opinion, you shouldn't put article's and author's in the same group,
>>>>>>>>>> there
>>>>>>>>>> is a 1/s write speed limit on entity groups, if you put them in the
>>>>>>>>>> same
>>>>>>>>>> entity group, you could hit this limit more easily
>>>>>>>>>>
>>>>>>>>>> You don't even have to use referenceproperty's - I would just put
>>>>>>>>>> the author key in an article StringProperty named "author" and query
>>>>>>>>>> for
>>>>>>>>>> it, if I were you
>>>>>>>>>>
>>>>>>>>>
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