Python MongoDB Tutorial – A Complete Beginner’s Guide

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Tags:- Python MongoDB

MongoDB is one of the most popular NoSQL databases used in modern applications. Unlike traditional relational databases, MongoDB stores data in flexible, JSON-like documents. In this tutorial, we’ll walk you through how to use MongoDB with Python, from setup to CRUD operations.


Table of Contents

  1. What is MongoDB?

  2. Why Use MongoDB with Python?

  3. Prerequisites

  4. Installing PyMongo

  5. Connecting to MongoDB

  6. Creating a Database and Collection

  7. CRUD Operations

    • Create (Insert)

    • Read (Find)

    • Update

    • Delete

  8. Complete Working Example

  9. Tips and Common Pitfalls


1. What is MongoDB?

MongoDB is a NoSQL, document-oriented database that stores data in BSON (Binary JSON). It's ideal for applications requiring scalability, flexibility, and real-time performance.


2. Why Use MongoDB with Python?

  • Python's dynamic typing and dictionaries align naturally with MongoDB's flexible schema

  • Great for data-driven applications, REST APIs, and rapid development

  • Supports horizontal scaling and real-time analytics


⚙️ 3. Prerequisites

  • Python installed (3.6+)

  • MongoDB Server installed and running (locally or remotely)

  • Basic knowledge of Python and JSON


4. Installing PyMongo

The official MongoDB driver for Python is PyMongo.

Install it using pip:

pip install pymongo

5. Connecting to MongoDB

import pymongo

client = pymongo.MongoClient("mongodb://localhost:27017/")

Connect to a Remote MongoDB Atlas Cluster:

client = pymongo.MongoClient("mongodb+srv://username:[email protected]/mydatabase")

6. Creating a Database and Collection

Create or Access a Database:

db = client["mydatabase"]

Create or Access a Collection (like a table in SQL):

collection = db["users"]

✅ MongoDB will create the database or collection only when you insert data.


✍️ 7. CRUD Operations in MongoDB

Create (Insert)

Insert one document:

user = {"name": "Alice", "age": 25}
collection.insert_one(user)

Insert multiple documents:

users = [
    {"name": "Bob", "age": 30},
    {"name": "Charlie", "age": 28}
]
collection.insert_many(users)

Read (Find)

Find one document:

user = collection.find_one()
print(user)

Find all documents:

for user in collection.find():
    print(user)

With a filter:

for user in collection.find({"age": {"$gt": 25}}):
    print(user)

✏️ Update

Update one document:

collection.update_one({"name": "Alice"}, {"$set": {"age": 26}})

Update many documents:

collection.update_many({}, {"$set": {"verified": True}})

❌ Delete

Delete one:

collection.delete_one({"name": "Bob"})

Delete many:

collection.delete_many({"verified": False})

8. Complete Working Example

import pymongo

# Connect to MongoDB
client = pymongo.MongoClient("mongodb://localhost:27017/")
db = client["company"]
employees = db["employees"]

# Insert documents
employees.insert_many([
    {"name": "Alice", "role": "Engineer", "salary": 75000},
    {"name": "Bob", "role": "Manager", "salary": 90000}
])

# Read documents
print("All Employees:")
for emp in employees.find():
    print(emp)

# Update a document
employees.update_one({"name": "Alice"}, {"$set": {"salary": 80000}})

# Delete a document
employees.delete_one({"name": "Bob"})

9. Tips and Common Pitfalls

Tip / Pitfall Advice
MongoDB is schema-less You can store any structure, but plan your schema wisely
_id field MongoDB auto-generates a unique _id, but you can assign your own
JSON != BSON MongoDB stores documents in BSON, which supports more data types
Connection errors Ensure MongoDB server is running and accessible
Use indexes For large datasets, create indexes on fields you query often

Summary Table

Operation Function
Insert One insert_one()
Insert Many insert_many()
Find One find_one()
Find Many find()
Update One update_one()
Update Many update_many()
Delete One delete_one()
Delete Many delete_many()

Final Thoughts

Python and MongoDB make a powerful pair for developers who need flexibility and performance. With PyMongo, working with MongoDB is simple and intuitive, especially if you're used to Python dictionaries and JSON structures.

Whether you're building a small project or a large-scale system, MongoDB's document model and Python's flexibility can help you move fast and build efficiently.

 

Tips and Tricks


What is pass in Python?

Python | Pass Statement

The pass statement is used as a placeholder for future code. It represents a null operation in Python. It is generally used for the purpose of filling up empty blocks of code which may execute during runtime but has yet to be written.

 

def myfunction():
    pass

 


How can you generate random numbers?

Python | Generate random numbers

Python provides a module called random using which we can generate random numbers. e.g: print(random.random())

 

 

We have to import a random module and call the random() method as shown below:

 import random

 print(random.random())

The random() method generates float values lying between 0 and 1 randomly.


To generate customized random numbers between specified ranges, we can use the randrange() method
Syntax: randrange(beginning, end, step)
 

import random

print(random.randrange(5,100,2))

 


What is lambda in Python?

Python | Lambda function

A lambda function is a small anonymous function. This function can have any number of parameters but, can have just one statement.
 

 

Syntex: 
lambda arguments : expression
 

a = lambda x,y : x+y

print(a(5, 6))

It also provides a nice way to write closures. With that power, you can do things like this.

def adder(x):
    return lambda y: x + y

add5 = adder(5)

add5(1)    #6

As you can see from the snippet of Python, the function adder takes in an argument x and returns an anonymous function, or lambda, that takes another argument y. That anonymous function allows you to create functions from functions. This is a simple example, but it should convey the power lambdas and closures have.
 


What is swapcase() function in the Python?

Python | swapcase() Function

It is a string's function that converts all uppercase characters into lowercase and vice versa. It automatically ignores all the non-alphabetic characters.
 

string = "IT IS IN LOWERCASE."  

print(string.swapcase())  

 


How to remove whitespaces from a string in Python?

Python | strip() Function | Remove whitespaces from a string 

To remove the whitespaces and trailing spaces from the string, Python provides a strip([str]) built-in function. This function returns a copy of the string after removing whitespaces if present. Otherwise returns the original string.
 

string = "  Python " 
 
print(string.strip())  

 


What is the usage of enumerate() function in Python?

Python | enumerate() Function

The enumerate() function is used to iterate through the sequence and retrieve the index position and its corresponding value at the same time.
 

lst = ["A","B","C"] 
 
print (list(enumerate(lst)))

#[(0, 'A'), (1, 'B'), (2, 'C')]

 


Can you explain the filter(), map(), and reduce() functions?

Python | filter(), map(), and reduce() Functions

  • filter()  function accepts two arguments, a function and an iterable, where each element of the iterable is filtered through the function to test if the item is accepted or not.
    >>> set(filter(lambda x:x>4, range(7)))
    
    # {5, 6}
    
    

     

  • map() function calls the specified function for each item of an iterable and returns a list of result

    >>> set(map(lambda x:x**3, range(7)))
    
    # {0, 1, 64, 8, 216, 27, 125}

     

  • reduce() function reduces a sequence pair-wise, repeatedly until we arrive at a single value..
     

    >>> reduce(lambda x,y:y-x, [1,2,3,4,5])
    
    # 3
    

    Let’s understand this:

    2-1=1
    3-1=2
    4-2=2
    5-2=3

    Hence, 3.

 


What is a namedtuple?

Python | namedtuple

A namedtuple will let us access a tuple’s elements using a name/label. We use the function namedtuple() for this, and import it from collections.

>>> from collections import namedtuple

#format
>>> result=namedtuple('result','Physics Chemistry Maths') 

#declaring the tuple
>>> Chris=result(Physics=86,Chemistry=92,Maths=80) 

>>> Chris.Chemistry
# 92

 


Write a code to add the values of same keys in two different dictionaries and return a new dictionary.

We can use the Counter method from the collections module

from collections import Counter

dict1 = {'a': 5, 'b': 3, 'c': 2}
dict2 = {'a': 2, 'b': 4, 'c': 3}

new_dict = Counter(dict1) + Counter(dict2)


print(new_dict)
# Print: Counter({'a': 7, 'b': 7, 'c': 5})


 


Python In-place swapping of two numbers

 Python | In-place swapping of two numbers

>>> a, b = 10, 20
>>> print(a, b)
10 20

>>> a, b = b, a
>>> print(a, b)
20 10

 


Reversing a String in Python

Python | Reversing a String

>>> x = 'PythonWorld'
>>> print(x[: : -1])
dlroWnohtyP

 


Python join all items of a list to convert into a single string

Python | Join all items of a list to convert into a single string

>>> x = ["Python", "Online", "Training"]
>>> print(" ".join(x))
Python Online Training

 


python return multiple values from functions

Python | Return multiple values from functions

>>> def A():
	return 2, 3, 4

>>> a, b, c = A()

>>> print(a, b, c)
2 3 4

 


Python Print String N times

Python | Print String N times

>>> s = 'Python'
>>> n = 5

>>> print(s * n)
PythonPythonPythonPythonPython

 


Python check the memory usage of an object

Python | Check the memory usage of  an object

>>> import sys
>>> x = 100

>>> print(sys.getsizeof(x))
28