How do I get the ID of an object after persisting it in PyMongo?
Question
I have a PyMongo newbie question: If collection
is a PyMongo Collection and I use it to save an object with
obj = {'foo': 'bar'}
collection.insert(obj)
then MongoDB automatically generates an _id
field for obj
; once can confirm this with
print obj
which yields something like
{'foo': 'bar', '_id': ObjectId('4c2fea1d289c7d837e000000')}
My question is: How do I get that _id
back out in such a way that I can use it?
For instance, if I want to delete obj
from the database, I would think that I would want to do something like
collection.remove(obj['_id'])
but when I try this I get the message
TypeError: 'ObjectId' object is unsubscriptable.
What's going on?
Solution
insert returns the _id of the inserted document.
and remove will remove based on _id, so try something like:
doc_id = db.test.insert({"foo": 1})
db.test.remove(doc_id)
OTHER TIPS
You just need to pass remove
a dict, just like you did insert
. So, to remove a document based on its _id
value, do something like:
collection.remove({'_id': ObjectId('4c2fea1d289c7d837e000000')})
You can just pass obj
.
for removing a object from document you have to mention condition As you can specify "_id" for a document ........
_id = db.test.insert({"foo": "test"})
db.test.remove({"_id":_id})