In MongoDB, insertion refers to adding new documents into a collection, while updating allows modifying existing documents. These operations are essential for managing dynamic datasets. With PyMongo library in Python, users can perform these tasks efficiently by establishing a connection to the database, creating or accessing collections and executing commands to insert or update data.

Insert data

Inserting data involves defining documents as dictionaries and adding them to a collection using insert_one() or insert_many(). Each inserted document automatically gets a unique _id field.

1. Use insert_one() for a single document.

collection.insert_one(doc1)

Parameter: doc1 represents a dictionary

2. Use insert_many() for multiple document.

collection.insert_many([doc1, doc2, doc3.....])

Parameter: [doc1, doc2, doc3,....] represents a list of dictionary

Viewing Inserted Documents

To view the inserted documents, MongoDB provides the find() method, which retrieves documents from a specific collection.

cursor = collection.find()
for doc in cursor:
print(doc)

Note: find() method works only within a single collection. It does not support querying across multiple collections simultaneously.

Let's see Example of Insertion of Data:- 

from pymongo import MongoClient
client = MongoClient("mongodb://localhost:27017/")
print("Connected successfully!")

# Access database and collection
db = client["mydatabase"]
collection = db["my_gfg_collection"]

# Documents to insert
emp_rec1 = {
    "name": "Mr. Geek",
    "eid": 24,
    "location": "Delhi"
}
emp_rec2 = {
    "name": "Mr. Shaurya",
    "eid": 14,
    "location": "Delhi"
}

# Insert documents
rec_id1 = collection.insert_one(emp_rec1)
rec_id2 = collection.insert_one(emp_rec2)

print("Data inserted with record IDs:")
print("Record 1 ID:", rec_id1.inserted_id)
print("Record 2 ID:", rec_id2.inserted_id)

# Display inserted documents
print("\nInserted records:")
for record in collection.find():
    print(record)

Output

Update data

Updating data involves modifying existing documents in a collection using update_one() or update_many(). These methods require a filter to match documents and an update operation to specify the changes.

With pymongo, updates can be easily applied using update operators like $set or $currentDate.

1. Use update_one() to update a single matching document

collection.update_one(filter, update)

Parameter:

• filter a dictionary specifying the condition to match documents (e.g., {"eid": 101})
• update a dictionary that defines the changes to apply (e.g., {"$set": {"name": "Updated Name"}})

2. Use update_many() to update all documents that match a condition

collection.update_many(filter, update)

Parameter:

• filter a dictionary specifying the matching criteria
• update a dictionary with update operators and values

Common Update Operators

1. $set: Updates the value of a specified field. If the field doesn't exist, it will be created.

{"$set": {"field": "value"}}

2. $currentDate: Sets the field to the current date or timestamp.

{"$currentDate": {"lastModified": True}}

Let's see Example of Updation of Data:- 

from pymongo import MongoClient
client = MongoClient("mongodb://localhost:27017/")
print("Connected successfully!")

# Access database and collection
db = client["mydatabase"]
collection = db["my_gfg_collection"]

# Update all employee documents where eid is 24
result = collection.update_many(
    {"eid": 24},
    {
        "$set": {
            "name": "Mr. GeeksforGeeks"
        },
        "$currentDate": {
            "lastModified": True
        }
    }
)

# Display update result
print("Matched documents:", result.matched_count)
print("Modified documents:", result.modified_count)

# Display all records in the collection
print("\nUpdated records:")
for record in collection.find():
    print(record)

Output

To find number of documents or entries in collection that are updated, use:

print(result.matched_count)

Here output would be 1.

Related Articles:

• Insert Method
• Update Method
• Logical query operators
• Comparison query operators
• Projection Operators