Insert and Update Data - Python MongoDB
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.
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