How to do "insert if not exist else update" with mongoengine?

Question

I'm working with mongoengine in Django,
this is my document defination:

class Location(mongoengine.Document):  
    user_id = mongoengine.IntField(required=True)  
    point = mongoengine.GeoPointField(required=True)

I want to do this:
given a user_id and a point:
if there is no document that have this user_id, create one with the user_id and point and save it;
else update the document with user_id with point.
Can I do this in one statement with mongoengine?

Solution 1

Note that get_or_create is now scheduled to be deprecated, because with no transaction support in MongoDB it cannot ensure atomicity.

The preferred way is update with upsert:

Location.objects(user_id=user_id).update_one(set__point=point, upsert=True)

More on upserts on the MongoDB documentation.

Solution 2

There is a new way to do it since version 0.9 (explained here):

location = Location.objects(user_id=user_id).modify(upsert=True, new=True, set__point=point)

It returns the created or updated object.

Solution 3

this is what I came up with:

location = Location.objects.get_or_create(user_id=user_id)[0]  
location.point = point  
location.save()

Solution 4

Or you can add a method to your class object via:

class Location(mongoengine.Document):  
    user_id = mongoengine.IntField(required=True)  
    point = mongoengine.GeoPointField(required=True)

    def register(self):
        # if doesnt exist, create user id and point field
        if not Location.objects(user_id=self.user_id):
            self.user_id = self.user_id
            self.point = self.point
            self.save()
            return True
        # does exist, do nothing
        else:
            return False

View more solutions

Comments

[mac]

possible duplicate of mongodb: insert if not exists - The answer is: use upsert.

[wong2]

@mac I think there maybe something even simpler.

[Ross]

location, created = Location.objects.get_or_create(user_id=user_id) Is the preferred way of doing it! But yes that will do what you need!

[Inactivist]

get_or_create() is now deprecated. upsert is recommended by the Mongoengine crew. See @NCao's answer for more info.

[arthur.sw]

How can I do the same thing but with user_id==-1 when the object does not exist?

[Nicolas Cortot]

@arthur.sw with MongoDB, the object ID for a new document is generated client-side, so you just need to create a new ID with user_id= ObjectId().

[arthur.sw]

There is a new way to do it since version 0.9 (explained here): location = Location.objects(user_id=user_id).modify(upsert=True, new=True, set__point=point)

[Hieu]

There is upsert_one method too: docs.mongoengine.org/…

[Paul Miller]

What's the reason for the lines self.user_id = self.user_id self.point = self.point? Thanks