Google appengine, Cannot fetch data from child model
My bulkloader.yaml looks like this:
- import: models
transformers:
- model: models.Company
connector: csv
connector_options:
encoding: utf_8
columns: from_header
property_map:
- property: __key__
external_name: companyid
import_transform: int
export_transform: transform.key_id_or_name_as_string
- property: name
external_name: name
- model: models.Home
connector: csv
connector_options:
encoding: utf_8
columns: from_header
property_map:
- property: __key__
external_name: listid
import_transform: int
export_transform: transform.key_id_or_name_as_string
- property: companyid
external_name: companyid
import_transform: transform.create_foreign_key('Company')
export_transform: transform.key_id_or_name_as_string
- property: address
external_name: address
- model: models.Bid
connector: csv
connector_options:
encoding: utf_8
columns: from_header
property_map:
- property: __key__
external_name: listid
import_transform: int
export_transform: transform.key_id_or_name_as_string
- property: listid
external_name: listid
import_transform: transform.create_foreign_key('Home',key_is_id=True)
export_transform: transform.key_id_or_name_as_string
- property: bidtext
external_name: bidtext
import_transform: db.Text
My models.py looks like this
from google.appengine.ext import db
# Models
class Company(db.Model):
"""Models a real estate company"""
companyid = db.Key()
name = db.StringProperty()
class Home(db.Model):
"""Models an apartment, house, villa etc and its selling details"""
listid = db.Key()
companyid = db.ReferenceProperty(Company, collection_name='company')
address = db.StringProperty()
class Bid(db.Model):
"""Models bidding against a listid from Home model"""
listid = db.ReferenceProperty(Home, collection_name='biddings')
bidtext = db.TextProperty()
I have uploaded the data on my local dev server and i can view the data using http://localhost:9999/_ah/admin/datastore. So data is uploaded and exists. I see the foreign keys too.
I am not able to access child data based on parent object. It returns empty. Below pasted is what i have been executing in interactive console on local dev datastore:
from google.appengine.ext import db
from models import Home,Bid,Company
#can access parent data from child i.e. Home
bd = Bid.get_by_id(4242)
hhh = Home.get_by_id(int(bd._listid.name()))
print hhh.state
#Again, can access parent data from child i.e. Company
h = Home.get_by_id(4242)
print h.address
c = Company.get_by_id(int(h._companyid.name()))
print c.website
#Cann开发者_C百科ot find any data here (biddings is a collection name defined in Bid model)
b = Bid.gql("WHERE listid = :1", h)
for x in h.biddings:
print x.bidtext
Output:
London
Riverview 24,
http://www.houses.com/
Alright I found what i was doing wrong. In my bulkloader.yaml, i was referencing entities as models instead of kind.
Once i used
- kind: Home
instead of
- model: models.Home
Also i used key_is_id=True at both the foreign key references to solve the problem of finding parent and child data.
Now this is how i access my parent and child data
from google.appengine.ext import db
from models import Home,Bid,Company
#get home object
h = Home.get_by_id(4242)
print h.address
#get parent values
print h.companyid.website
#get child values
b = Bid.gql("WHERE listid = :1", h.key())
for xb in b:
print xb.bidtext
I hope this helps some noob like me cause i wasted a lot of time behind this. Thank you everyone who took time to respond to this thread.
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