You can, do two calls to the datastore
# first get the required BaseObject
base = BaseObject.all().filter(.......).get()
if not base: return
# then get the SubObjects that link to this BaseObject with the right fields
subobjs = SubObject.all.filter('baseref =',
base.reffield).filter('somefield >', subSelectValue).fetch(1000)
if not subobjs: return
2009/6/5 mscwd01 <[email protected]>:
>
> So the relational model I mentioned would be the better option?
>
> Its a pity there isnt a feature to select desired baseObjects and then
> search within SubObjects linked to that object within a DataStore
> call...
>
> On Jun 5, 9:50 pm, djidjadji <[email protected]> wrote:
>> One huge object would be very inefficient. You have to retrieve the
>> whole lot every time you get() a BaseObject. You are limited to a
>> total size of 1 Mbyte per object.
>>
>> Much cleaner is the approach with the two object Models. Now you can
>> have an unlimited number of SubObjects and let the index do most of
>> the work of fetching only the SubObjects that are important.
>>
>> 2009/6/5 mscwd01 <[email protected]>:
>>
>>
>>
>> > Hi,
>>
>> > I have a question regarding the best method of storing a complex
>> > object which may grow to be very large in size.
>>
>> > I have an object 'BaseObject' which has a field of type
>> > List<SubObject>. I wish to add many SubObject's to BaseObjects,
>> > perhaps millions. When querying a SubObject I will first retrieve the
>> > BaseObject and then perform a query on its list of SubObjects to find
>> > the objects I need.
>>
>> > Now, is it a good idea to store objects in this way? I.e. having a
>> > BaseObject which comprises an enormous list of SubObjects?
>>
>> > Another method of doing this would be to take the relational database
>> > approach and have a BaseObject and SubObjects table where SubObjects
>> > reference BaseObjects via an ID. However, I would really like to
>> > maintain an object approach.
>>
>> > What are your views on this? Any feedback would be greatly
>> > appreciated.
>>
>> > Thanks
> >
>
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