When you need to update many records at once, which can be the case when you need a new field added to all the existing records, use the update_many() function.
As with find_one_and_update(), we first need to create a filter for the records that we want to update.
The following code tells us how to update multiple records using PyMongo:
from pymongo import MongoClient
client = MongoClient('localhost', 27017)
db = client.pythonbicookbook
customers = db.customers
result = customers.update_many(
{ 'first_name': {
'$exists': True }
},
{'$currentDate': {
'updated_at': { $type: "timestamp" }
},
'$set': {
'contacted': False
}})
print(result.matched_count)In this recipe, we are setting the contacted key to False for all the customer records that have a first name and updated_at to the time of the update. We then print out the count of records that were updated. As in previous recipes, we provide a filter as the first argument followed by the update to be performed.
Instead of manually setting the updated_at field, we use another update operator: $currentDate, which will set the given field, in this case updated_at, to the current timestamp using the $type operator.