mongodb: upserting: only set value if document is being inserted

Question

Considering a simple mongo document structure:

{ _id, firstTime, lastTime }

The client needs to insert a document with a known ID, or update an existing docu

Answer 1

I ran into a very similar problem when attempting to upsert documents based on existing content--maybe this solution will work for you also:

Try removing the _id attribute from your record and only use it in the query portion of your update (you'll have to translate from pymongo speak...)

myid = doc.get('_id')
del doc['_id']
mycollection.update({'_id':myid}, {'$set':doc}, upsert=True)