Maybe i have an understanding problem. I try to make 2 tabeles in one database. But additionaly i need to have some temporary values in one class that i doen´t want to write to the database.
I try to switch to peewee and read the dokumentation but i find no solution at my own.
without peewee i would make an init method where i write my attributes. But where did i have to write them now?
from peewee import *
import datetime
db = SqliteDatabase('test.db', pragmas={'foreign_keys': 1})
class BaseModel(Model):
class Meta:
database = db
class Sensor(BaseModel):
id = IntegerField(primary_key=True)
sort = IntegerField()
name = TextField()
#def __init__(self):
#self.sometemporaryvariable = "blabla"
def meineparameter(self, hui):
self.hui = hui
print(self.hui)
class Sensor_measure(BaseModel):
id = ForeignKeyField(Sensor, backref="sensorvalues")
timestamp = DateTimeField(default=datetime.datetime.now)
value = FloatField()
class Meta:
primary_key = CompositeKey("id", "timestamp")
db.connect()
db.create_tables([Sensor_measure, Sensor])
sensor1 = Sensor.create(id=2, sort=20, name="Sensor2")
#sensor1.sometemporaryvariable = "not so important to write to the database"
sensor1.save()
Remember to call super() whenever overriding a method in a subclass:
class Sensor(BaseModel):
id = IntegerField(primary_key=True)
sort = IntegerField()
name = TextField()
def __init__(self, **kwargs):
self.sometemporaryvariable = "blabla"
super().__init__(**kwargs)
I have a very big model in models.py:
simplified version is:
class MyModel(models.Model):
item_1 = models.FloatField(null=True, blank=True)
...
item_20 = models.FloatField(null=True, blank=True)
in views.py:
def form_valid(self, form_class):
instance = form_class.save(commit=False)
for i in range(1, 20):
name = 'item_' + str(i)
instance.name = i
With this the field name 'item_1' ... to 'item_20' in instance is not recogniced. Instead 'name' is added to instance like other new field...
How can I iterate and save my model?
Any suggestion?
Thanks!!!
You should probably use setattr in order to loop through the fields and set the values in them. Try this:
def form_valid(self, form_class):
instance = form_class.save(commit=False)
for i in range(1, 20):
name = 'item_' + str(i)
setattr(instance, name, value) # Where value is the data you wanted to save in the field `name`
Similary user getattr() to get the data by looping through the class instance.
What's wrong with my query?
Here are my models:
class Positions(ndb.Model):
title = ndb.StringProperty(indexed=True)
summary = ndb.TextProperty()
duties = ndb.TextProperty()
dateCreated = ndb.DateTimeProperty(auto_now_add=True)
dateUpdated = ndb.DateTimeProperty(auto_now=True)
class Applicants(ndb.Model):
name = ndb.StringProperty(indexed=True)
position = ndb.KeyProperty(kind=Positions,repeated=True)
file = ndb.BlobKeyProperty()
dateCreated = ndb.DateTimeProperty(auto_now_add=True)
dateUpdated = ndb.DateTimeProperty(auto_now=True)
Here is my query:
class AdminPositionInfoHandler(BaseHandler):
def get(self,positionKeyId):
user = users.get_current_user()
if users.is_current_user_admin():
positionKey = ndb.Key('Positions',int(positionKeyId))
position = positionKey.get()
applicants = Applicants.query(position=position.key).fetch() # the query
values = {
'position': position,
'applicants': applicants,
}
self.render_html('admin-position-info.html',values)
else:
self.redirect(users.create_login_url(self.request.uri))
What seems to be wrong in using the query:
applicants = Applicants.query(position=position.key).fetch()
I got this error:
File "C:\xampp\htdocs\angelstouch\main.py", line 212, in get
applicants = Applicants.query(position=position.key).fetch()
...
TypeError: __init__() got an unexpected keyword argument 'position'
I also tried using positionKey instead of position.key:
applicants = Applicants.query(position=positionKey).fetch()
I got this from "Ancestor Queries" section of GAE site:
https://developers.google.com/appengine/docs/python/ndb/queries
You don't pass arguments to query like that - ndb uses overridden equality/inequality operators, so you can express queries more 'naturally', with '==', '<', '>' etc., so:
applicants = Applicants.query(Applications.position==position.key).fetch()
The section in the on Filtering by Property Values gives some more examples.
(ancestor is a special-case for queries - it isn't a model property)
I have two entities (events and users). Each user has several events, but I don't want them to be stored within a StructuredProperty, because in future it should be possible to have multiple creators/admins. Now I have the problem, that User needs the Event Class for definition and vice versa. How can I implement the intended structure?
Two models with mutual relations.
class Event(EndpointsModel):
_message_fields_schema = ("id", "name", "creator",
"datetime", "place", "category", "participants")
creator = ndb.KeyProperty(kind=User)
participants = ndb.KeyProperty(kind=User, repeated=True)
name = ndb.StringProperty()
datetime = ndb.DateTimeProperty(auto_now_add=True)
place = ndb.GeoPtProperty()
category = ndb.StringProperty(choices=('all', 'drinking'))
class User(EndpointsModel):
_message_fields_schema = ("id", "name", "password", "events")
name = ndb.StringProperty()
password = ndb.StringProperty()
events = ndb.KeyProperty(kind=Event, repeated=True)
def create_event(self, e_name, e_datetime, e_place, e_category):
event = Event(name=e_name, creator = self.key, datetime=e_datetime, place=e_place, category=e_category)
event.put()
self.events.append(event)
self.put()
def get_events(self):
return ndb.get_multi(self.events)
Error Message:
NameError: name 'User' is not defined
EDIT 1:
I changed the kind to a string, containing the class name, like Greg suggested it. But it does not work too.
class Category(EndpointsModel):
_message_fields_schema = ("id", "name", "parent")
name = ndb.StringProperty()
parent = ndb.KeyProperty(kind='Category', default=None)
class Event(EndpointsModel):
_message_fields_schema = ("id", "name", "creator", "datetime",
"place", "category")
participants = ndb.KeyProperty(kind='User', repeated=True)
creator = ndb.KeyProperty(kind='User')
name = ndb.StringProperty()
datetime = ndb.DateTimeProperty(auto_now_add=True)
place = ndb.GeoPtProperty()
category = ndb.KeyProperty(Category)
class User(EndpointsModel):
_message_fields_schema = ("id", "name", "password")
name = ndb.StringProperty()
password = ndb.StringProperty()
events = ndb.KeyProperty(Event, repeated=True)
Now I receive the following stack trace:
ERROR 2014-01-21 09:38:39,764 service.py:191] Encountered unexpected error from ProtoRPC method implementation: BadValueError (Expected Key, got [])
Traceback (most recent call last):
File "/home/chris/Downloads/google_appengine/lib/protorpc-1.0/protorpc/wsgi/service.py", line 181, in protorpc_service_app
response = method(instance, request)
File "/home/chris/Downloads/google_appengine/lib/endpoints-1.0/endpoints/api_config.py", line 1321, in invoke_remote
return remote_method(service_instance, request)
[...]
value = self._call_shallow_validation(value)
File "/home/chris/Downloads/google_appengine/google/appengine/ext/ndb/model.py", line 1227, in _call_shallow_validation
return call(value)
File "/home/chris/Downloads/google_appengine/google/appengine/ext/ndb/model.py", line 1274, in call
newvalue = method(self, value)
File "/home/chris/Downloads/google_appengine/google/appengine/ext/ndb/model.py", line 1927, in _validate
raise datastore_errors.BadValueError('Expected Key, got %r' % (value,))
BadValueError: Expected Key, got []
You can use strings in the KeyProperty constructor to refer to kinds that don't have a model definition:
class Event(ndb.Model):
participants = ndb.KeyProperty(kind='User', repeated=True)
You can not create such references to the entities. Here is somo solutions:
1. You must use normal StringProperty for Event.creator or other id for User instance
2. Remove evens from class User - you can reach to evens by index on class Events
3. Use third entity model like this:
class EventCreator(EndpointsModel):
creator = ndb.KeyProperty(kind=User)
event = ndb.KeyProperty(kind=Event)
and from class User remove creator & from class Event remove
You could specify the key properties without the kind parameter (it is optional) and then do a manual check in your constructor or a pre-put hook or something like that -- or maybe not even worry about the kind:
class Event(EndpointsModel):
creator = ndb.KeyProperty()
# Constructor option
def __init__(self, *args, **kwargs):
super(Event, self).__init__(*args, **kwargs)
if 'creator' in kwargs and kwargs['creator'] != 'User':
raise Exception('oh no')
# Hook option
_pre_put_hook(self):
if self.creator and self.creator.kind() != 'User':
raise Exception("oh no")
The actual syntax will probably be slightly different. Feel free to edit.
class ProjectCategory(db.Model):
name = db.StringProperty("Category name", required = True)
def __str__(self):
return str(self.name)
class Project(db.Model):
name = db.StringProperty("Name", required = True)
category = db.ReferenceProperty(ProjectCategory)
description = db.TextProperty("Description", required = True)
#file_name = db.StringProperty("File name", required = True)
file = db.BlobProperty("Image")
whenstarted = db.DateTimeProperty("Start time")
whenended = db.DateTimeProperty("End Time")
def __str__(self):
return str(self.title)
How to get all Projects where category is CatName
hmm
db.GqlQuery("SELECT * FROM Project WHERE category = :1", "CatName")
don't work ?
The query does not work because you are passing a "CatName" string instead of a ProjectCategory instance's key.
Retrieve your desired ProjectCategory entity from Datastore first with:
pjc = GqlQuery("SELECT * FROM ProjectCategory WHERE name = :1", "CatName").get()
then use it as parameter in the query like this:
db.GqlQuery("SELECT * FROM Project WHERE category = :1", pjc.key())
A second approach is to use the implicit modelname_set Property of the ProjectCategory instance:
pjc = GqlQuery("SELECT * FROM ProjectCategory WHERE name = :1", "CatName").get()
pjc.project_set.fetch(10) #should contains some CatName projects