Mongoengine find document without a field

Question

I need to find a document in the collection of Chat that contains no deal field. According to the documentation exists checks if the field exist, and first, is used to retrieve the first result, but the next line

Chat.objects.first(deal__exists=False)

raises TypeError: first() got an unexpected keyword argument 'deal__exists'

That's the Chat scheme

class Chat(Document):
    id = IntField(primary_key=True)
    name = StringField(default=CHANNEL_NAME)
    invite_link = StringField(default=None)
    deal = ReferenceField("Deal", default=None)

and current state of the only document in the collection:

{
    "_id" : XXXXXXXXX,
    "name" : "XXXXX",
    "invite_link" : "https://t.me/joinchat/XXXXXXXXXXXXXXXXXXXXXX"
}

Value none for the deal gives the same result

score 2 · Accepted Answer · edited Jul 04 '19 at 13:58

2

You can try :

Chat.objects.get(deal__exists=False)

or

Chat.objects(deal__exists=False)[0]

to find the first result.

edited Jul 04 '19 at 13:58

Sadderdaze

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answered Jul 04 '19 at 13:52

Ravi Shankar Bharti

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Results in `KeyError: 0` – Sadderdaze Jul 04 '19 at 13:55
do you have documents where deal doesnt exists? – Ravi Shankar Bharti Jul 04 '19 at 13:57
Yep, there is currently only one document in the collection and current state of the document is in the question – Sadderdaze Jul 04 '19 at 13:59
1

mongoengine maintainer here, this is actually correct. Double check your document from a mongo shell, I believe your document is different and has `deal: None` instead of not having the `deal` key – bagerard Jul 04 '19 at 21:17

Sadderdaze · Answer 2 · 2019-07-04T15:05:22.703

0

Took me a while.

First of all, method first should be applied to the result of Chat.objects(deal=None). Just like Chat.objects(deal=None).first().

And it should not be used in with statement as it raises AttributeError: __enter__. Here are more details on the error

edited Jul 04 '19 at 15:05

answered Jul 04 '19 at 14:58

Sadderdaze

304
3
14

Mongoengine find document without a field

2 Answers2