Python db.filter() strangeness

[sergey]

Hi all!
I have spend more my time to find bug in my code, source of which is a
feature of the filtering methods:
Сompare the two codes and try to quickly find a mistake in one of them
(which you do not show any IDE):

code 1:

from google.appengine.ext import db
class Item(db.Model):
name = db.StringProperty()

Item(name= 'ipad').put()
ipads = Item.all().filter('name =', 'ipad').count()

print ipads

code 2:

from google.appengine.ext import db
class Item(db.Model):
name = db.StringProperty()

Item(name= 'ipad').put()
ipads = Item.all().filter('name=', 'ipad').count()

print ipads


what the code is correct?

i think you need to to fix this feature in future releases

p.s. filter('name=', 'ipad') != filter('name =', 'ipad')

[Robert Kluin]

Hi Sergey,
This is a known and expected behavior, it is mentioned in the docs:
http://code.google.com/appengine/docs/python/datastore/queryclass.html#Query_filter

Datastore property names don't have to be valid Python identifiers.
When there is no space in the filter def, equality is assumed. I do
agree that this is an easy mistake to make. But, I know I've got lots
of filters in my code that omit the operator for brevity. And who
knows, someone probably also has an "=" in a property name.

Robert

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[Stephen]

2011/6/26 Robert Kluin <robert...@gmail.com>:

>
> And who knows, someone probably also has an "=" in a property name.

Google knows. They could map over all properties in the datastore
checking for names which end in '='. I would be surprised if it's not
0.

[Robert Kluin]

You have more faith than I do. :)

[Jay Young]

If anyone is base-64 encoding their property names, this would be highly likely.  Or, if anyone is mapping readable property names to a shorter alphabet to save on storage size, a property named "=" would also be a possibility.

[Branko Vukelic]

On Thu, Jun 23, 2011 at 10:50 AM, sergey <s.lya...@gmail.com> wrote:
> ipads = Item.all().filter('name =', 'ipad').count()

Sometimes happens to me in the form of typo. I've adopted this form:

ipads = Item.all().filter('name', 'ipad').count()

It's documented.

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Branko Vukelić
bra...@herdhound.com

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