CODEWITHSUNDEEP
pythonmongodb
iaswmn
iaswmn

Reputation: 39

MongoDB add increment to id

I have collections in MongoDB. I need to get values from collection. If values - none -> take values from other collection and set (id +=1) and save. My code: 

def get_next_sequence(self):
    client = MongoClient(self.__connection_string)
    db = client[self.__db_name]
    collection = db['counters']
    get_id = collection.find_one({'_id': 'breaks_column_id'})
    if get_id is None:
        db['counters'].insert_one({'_id': 'breaks_column_id', 'seq': 1})
        return 1
    else:
        get_id += 1
        db['counters'].update_one({'_id': 'breaks_column_id', 'seq': get_id})
        return get_id

when i debug this code -> error

TypeError: unsupported operand type(s) for +=: 'dict' and 'int'

Upvotes: 0

Views: 47

Answers (1)

Dan Ionescu
Dan Ionescu

Reputation: 3423

You can use mongoDb $inc operator to increment a field:

    def get_next_sequence(self):
        client = MongoClient(self.__connection_string)
        db = client[self.__db_name]
        collection = db['counters']
        result = collection.find_one({'_id': 'breaks_column_id'})
        print(result)
        if result is None:
            db['counters'].insert_one({'_id': 'breaks_column_id', 'seq': 1})
            return 1
        else:
            db['counters'].update_one({'_id': 'breaks_column_id'}, {'$inc' : {'seq' : 1}})
            # if run in paralel this won't return necessarely an accurate result
            return result['seq'] + 1

Upvotes: 1

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