
Python MongoDB Tutorial – How to Insert a Document Using PyMongo
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MongoDB is a document-oriented NoSQL database that stores data in flexible, JSON-like documents. In this tutorial, you'll learn how to insert documents into a MongoDB collection using Python with the PyMongo
library.
Whether you're working with a local MongoDB instance or a cloud-based MongoDB Atlas cluster, this guide covers all the basics with step-by-step explanations and code examples.
Table of Contents
-
What is a MongoDB Document?
-
Why Use PyMongo?
-
Prerequisites
-
Installing PyMongo
-
Connecting to MongoDB
-
Creating a Database and Collection
-
Inserting One Document
-
Inserting Multiple Documents
-
Verifying Insertions
-
Full Working Example
-
Tips and Common Pitfalls
1. What is a MongoDB Document?
A document in MongoDB is a set of key-value pairs, similar to a Python dictionary or a JSON object. For example:
{
"name": "Alice",
"email": "[email protected]",
"age": 25
}
Documents are stored in collections, which are similar to tables in relational databases.
2. Why Use PyMongo?
PyMongo is the official MongoDB driver for Python. It lets you:
-
Connect to MongoDB databases (local or cloud)
-
Perform CRUD operations (Create, Read, Update, Delete)
-
Work with Python dictionaries for document data
⚙️ 3. Prerequisites
-
Python 3 installed
-
MongoDB server (local or MongoDB Atlas)
-
Basic understanding of Python and JSON
4. Installing PyMongo
Install PyMongo using pip:
pip install pymongo
5. Connecting to MongoDB
Local MongoDB Server:
import pymongo
client = pymongo.MongoClient("mongodb://localhost:27017/")
MongoDB Atlas (Cloud):
client = pymongo.MongoClient("mongodb+srv://username:[email protected]/?retryWrites=true&w=majority")
Replace username
, password
, and cluster.mongodb.net
with your actual credentials.
6. Creating a Database and Collection
db = client["mydatabase"] # Create or access the database
collection = db["users"] # Create or access the collection
7. Inserting One Document
Use the insert_one()
method:
user = {"name": "Alice", "email": "[email protected]", "age": 25}
result = collection.insert_one(user)
print("Inserted ID:", result.inserted_id)
Explanation:
-
insert_one()
returns an object containing the_id
of the inserted document. -
MongoDB automatically adds an
_id
field if it's not provided.
8. Inserting Multiple Documents
Use the insert_many()
method for batch insertion:
users = [
{"name": "Bob", "email": "[email protected]", "age": 30},
{"name": "Charlie", "email": "[email protected]", "age": 28}
]
result = collection.insert_many(users)
print("Inserted IDs:", result.inserted_ids)
✅ 9. Verifying Insertions
To confirm your documents were inserted:
for user in collection.find():
print(user)
You can also filter:
user = collection.find_one({"name": "Alice"})
print(user)
10. Full Working Example
import pymongo
# Connect to MongoDB
client = pymongo.MongoClient("mongodb://localhost:27017/")
# Create database and collection
db = client["mydatabase"]
collection = db["users"]
# Insert one document
user = {"name": "Alice", "email": "[email protected]", "age": 25}
result_one = collection.insert_one(user)
print("Inserted one ID:", result_one.inserted_id)
# Insert multiple documents
users = [
{"name": "Bob", "email": "[email protected]", "age": 30},
{"name": "Charlie", "email": "[email protected]", "age": 28}
]
result_many = collection.insert_many(users)
print("Inserted many IDs:", result_many.inserted_ids)
# Verify insertion
print("All users in database:")
for user in collection.find():
print(user)
11. Tips and Common Pitfalls
Tip / Pitfall | Advice |
---|---|
MongoDB auto-generates _id |
You can also manually set _id , but ensure it's unique |
Inconsistent data formats | MongoDB allows schema-less data; maintain consistency yourself |
Duplicate key error | Avoid inserting documents with duplicate _id |
Empty insert | Don't call insert_many([]) – it will raise an error |
Connection error | Ensure MongoDB is running locally or credentials are correct for Atlas |
Conclusion
Inserting documents into MongoDB using Python is straightforward with PyMongo
. Whether you're inserting a single document or multiple records at once, the process is intuitive and efficient.
This flexibility makes MongoDB a strong choice for Python developers building scalable, dynamic applications.
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=3Hence, 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