Hey Erwin,
Try it. Here's some sample code:
class T(db.Model):
sp = db.StringProperty()
ip = db.IntegerProperty()
T(key_name='test', sp='some str', ip=7).put()
# stop. go look in the datastore viewer.
# now, comment out the def of 'sp' and the put(), then rerun with
test_t = T.get_by_key_name('test')
test_t._entity.pop('sp', None)
test_t.put()
Robert
On Wed, Apr 6, 2011 at 23:45, Erwin Streur <[email protected]> wrote:
> Robert,
>
> Are you sure that this is going to work? In GAE there is a significant
> difference between a property not being set/not existing at all and
> being set to null/None.
>
> Erwin
>
> On 5 apr, 08:27, Robert Kluin <[email protected]> wrote:
>> Hey Greg,
>> Assuming you are deleting the property definition from the Model,
>> then I think you can also use:
>>
>> your_entity._entity.pop('property_to_delete', None)
>>
>> It is shorter, and probably a little clearer.
>>
>> Robert
>>
>>
>>
>> On Tue, Apr 5, 2011 at 00:17, Greg <[email protected]> wrote:
>> > I've stumbled across what looks like a neat way to remove obsolete
>> > properties from entities, without having to switch models to Expando
>> > and back again. I convert the entity to a protocol buffer, which
>> > reveals the obsolete properties. Then I remove them, convert back to
>> > an entity and save it.
>>
>> > So far my testing has shown this doesn't have any ill effects, but I'd
>> > like feedback in case what I'm doing is dangerous. In particular, I
>> > don't understand what would happen to the indexes for the removed
>> > properties - how does the datastore handle these?
>>
>> > Cheers
>> > Greg.
>>
>> > # !!! EXPERIMENTAL CODE !!!
>> > # !!! USE ENTIRELY AT YOUR OWN RISK !!!
>> > # !!! NOT ENDORSED BY GOOGLE (YET) !!!
>>
>> > from google.appengine.ext import db
>>
>> > def remove_stale_properties(e):
>> > current_properties=e.properties().keys()
>> > epb=db.model_to_protobuf(e)
>> > for i in reversed(range(len(epb.property_))):
>> > if epb.property_[i].name() not in current_properties:
>> > logging.info('Deleting property %s:%s'%
>> > (epb.property_[i].name(),epb.property_[i].value()))
>> > del epb.property_[i]
>> > for i in reversed(range(len(epb.raw_property_))):
>> > if epb.raw_property_[i].name() not in current_properties:
>> > logging.info('Deleting raw property %s:%s'%
>> > (epb.raw_property_[i].name(),epb.raw_property_[i].value()))
>> > del epb.raw_property_[i]
>> > return db.model_from_protobuf(epb)
>>
>> > # Example usage
>>
>> > entity_list=Foo.all().fetch(1000)
>> > for entity in entity_list:
>> > entity=remove_stale_properties(entity)
>> > db.put(entity_list)
>>
>> > --
>> > You received this message because you are subscribed to the Google Groups
>> > "Google App Engine" group.
>> > To post to this group, send email to [email protected].
>> > To unsubscribe from this group, send email to
>> > [email protected].
>> > For more options, visit this group
>> > athttp://groups.google.com/group/google-appengine?hl=en.- Tekst uit
>> > oorspronkelijk bericht niet weergeven -
>>
>> - Tekst uit oorspronkelijk bericht weergeven -
>
> --
> You received this message because you are subscribed to the Google Groups
> "Google App Engine" group.
> To post to this group, send email to [email protected].
> To unsubscribe from this group, send email to
> [email protected].
> For more options, visit this group at
> http://groups.google.com/group/google-appengine?hl=en.
>
>
--
You received this message because you are subscribed to the Google Groups
"Google App Engine" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/google-appengine?hl=en.
