Merge Mongodb Collection And A Python Dict

I have a collection that look something like that : { {'name': 'aaa', 'value': 100}, {'name': 'bbb', 'value': 50}, {'name': 'ccc', 'value': 200}, } and imagine I have a dict

Solution 1:

You can try below code :

import pymongo
from pymongo import UpdateOne
import json
import sys

inputArray = [
    {"name": "aaa", "value": 40},
    {"name": "ccc", "value": -100},
    {"name": "ddd", "value": 200},
]

bulkArr = []

# Iterate over all dicts in a list & form the query,
# Here `upsert=True` helps to insert a new doc into collection if there is no match on `{"name": x['name']}`,
# If there is a match doc will be updated, You can use `$set` or any-other operator depends on your use case.
for x in inputArray:
    bulkArr.append(
        UpdateOne({"name": x['name']}, {'$inc': {'value': x['value']}}, upsert=True))

# print('[%s]' % ', '.join(map(str, bulkArr)))

try:
    result = db.collection.bulk_write(bulkArr) # Ensure db connection is established by this point
    # Opt for below - if you want to proceed on all dictionaries to be updated, even though an error occured in between for one dict
    # result = db.collection.bulk_write(bulkArr, ordered=False)
    print(result.bulk_api_result)
except:
    e = sys.exc_info()[0]
    print("An exception occurred ::", e) ## Get the ids failed if any & do re-try

Ref : bulk-write-operations

Solution 2:

You need to use update_one() with upsert=True with the $inc operator:

from pymongo import MongoClient
from bson.json_util import dumps

db = MongoClient()['mydatabase']

item1 = [
  {"name": "aaa", "value": 100},
  {"name": "bbb", "value": 50},
  {"name": "ccc", "value": 200}
]

item2 = [
  {"name": "aaa", "value": 40},
  {"name": "ccc", "value": -100},
  {"name": "ddd", "value": 200}
]

for item in [item1, item2]:
    for record in item:
        db.mycollection.update_one({'name': record.get('name')}, {'$inc': {'value': record.get('value')}}, upsert=True)

print(dumps(db.mycollection.find({}, {'_id': 0}), indent=4))

gives:

[
    {
        "name": "aaa",
        "value": 140
    },
    {
        "name": "bbb",
        "value": 50
    },
    {
        "name": "ccc",
        "value": 100
    },
    {
        "name": "ddd",
        "value": 200
    }
]