Thanks, Mike.
I think you are correct, in that I will have to turn my 60 property
model into, maybe 15 4 property models. That is a fragmented way to
carry my data, but at least it will scale, and not fill the query
memory with unused properties. Tailoring the objects to the views is
the proper way to be efficient and scale.
Yes, I am guilty of designing this relationally. I thought it made it
simple, but the GAE queries are not made to pull properties from an
entity, but the entity as an entire object. So, to pull the email
addresses out from your members, you have to either carry the email
addresses in a separate model, or limit the number per query to the
number of complete entities (all properties included) that will fit
into memory.
Let this be a lesson to any other new users who think they should just
import their SQL csv into the datastore.
So, back to the question... This now turns to syntax... My model list
properties by date, so I am wondering if I should use the
ReferenceProperty feature or not. If I want to just pull out all the
sales figures by date, what should I do?
Option 1)
class myDate(BaseModel):
Date = db.DateProperty()
class SalesVolume(BaseModel):
Date = db.ReferenceProperty(myDate,
collection_name='sales_ref')
Sales = db.FloatProperty()
class Hours(BaseModel):
Date = db.ReferenceProperty(myDate,
collection_name='hours_ref')
Hours = db.FloatProperty()
class NumberOne(BaseModel):
Date = db.ReferenceProperty(myDate,
collection_name='number1_ref')
NumberOne = db.FloatProperty()
If I want to just pull out ONLY the SalesVolume and Hours for each
date, what would my query look like? Remember, I do not want the
NumberOne in memory. Can I do it in one query? Do I need to do 2
separate queries? What purpose does the ReferenceProperty serve?
I think if I do a myDate.all().filter(...) , I still will get every
Related property put into the query.
Should I forget about the reference, and just do:
Option 2)
class SalesVolume(BaseModel):
Date = db.DateProperty()
Sales = db.FloatProperty()
class Hours(BaseModel):
Date = db.DateProperty()
Hours = db.FloatProperty()
class Number(BaseModel):
Date = db.DateProperty()
Number = db.FloatProperty()
Here, I end up with 3 separate models, and would certainly need 3
separate queries.
Any help on best practice here is greatly appreciated.
Thank you.
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