Python MongoDB – Update_many Query

Last Updated : 26 May, 2020

MongoDB is a NoSQL database management system. Unlike MySQL the data in MongoDB is not stored as relations or tables. Data in mongoDB is stored as documents. Documents are Javascript/JSON like objects. More formally documents in MongoDB use BSON. PyMongo is a MongoDB API for python. It allows to read and write data from a MongoDB database using a python script. It needs both python and mongoDB to be installed on the system.

Update_many()

Update function has been deprecated in newer versions of MongoDB (3.xx and above). Earlier update function could be used for both single updates and multiple using “multi = true”. But in newer versions of mongoDB it is recommended to use update_many() and update_one().

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning - Basic Level Course

The major difference is that the user needs to plan ahead if the query is going to be updating single or multiple documents.

Syntax:

db.collection.updateMany(
   <filter>,
   <update>,
   {
     upsert: <boolean>,
     writeConcern: <document>,
     collation: <document>,
     arrayFilters: [ <filterdocument1>, ... ],
     hint:  <document|string>
   }
)

Update Operators in MongoDB

Setting Values:

$set: Used to set a fields value.
$setOnInsert: Update value only if a new document insertion.
$unset: Remove the field and its value.

Numeric Operators:

$inc: Increases the value by a given amount.
$min/$max: returns minimum or maximum of value.
$mul: multiplies the values by a given amount.

Miscellaneous Operators:

$currentDate: Updates value of a field to current date.
$rename: Renames a field

Sample Database:

Some use cases we are going to see in this article where updating many records can be useful:

Changing or incrementing several elements based on a condition.
Inserting a new field to multiple or all documents.

Example 1: All the students with marks greater than 35 has been passed.

Python3

from pymongo import MongoClient
  
  
# Creating an instance of MongoClient 
# on default localhost
client = MongoClient('mongodb://localhost:27017')
  
# Accessing desired database and collection
db = client.gfg
collection = db["classroom"]
  
# Update passed field to be true for all
# students with marks greater than 35
collection.update_many(
    {"marks": { "$gt": "35" } },
        {
            "$set": { "passed" : "True" }
        }
)

Database After Query:

Example 2: New field called address added to all documents

Python

from pymongo import MongoClient
  
  
# Creating an instance of MongoClient 
# on default localhost
client = MongoClient('mongodb://localhost:27017')
  
# Accessing desired database and collection
db = client.gfg
collection = db["classroom"]
  
# Address filed to be added to all documents
collection.update_many(
        {},
        {"$set":
            {
                "Address": "value"
            }
        },
    
   # don't insert if no document found
   upsert=False,
   array_filters=None
   )

Database After query:

My Personal Notes

Related Articles

Related Articles

Python MongoDB – Update_many Query

Update_many()

Python3

Python