Delete one or more documents from a MongoDB collection using PyMongo

Overview:

A MongoDB collection consists of several JSON documents in binary format.
To delete records from a MongoDB collection, the PyMongo Python driver offers several variants of delete operation through the methods
- delete_one()
- delete_many()

Delete one document satisfying a filter condition:

To delete only one document, that meets the specified filter conditionamong several others, the method can be called on a object.
The example below specifies the condition for the single document that is to be deleted is {"red" : 123, "green" : 223}.

Example:

# import the python driver for MongoDB

from pymongo import MongoClient

# Create a MongoDB client

mongoDBConnection = MongoClient('mongodb://localhost:27017/')

# Get a collection instance

database = mongoDBConnection.sample

collection = database.sample1

# Print the collection before deleting a single record meeting the criteria

print("Before deletion:");

for mongoDBdocument in collection.find():

print(mongoDBdocument)

# Delete one record satisfying the filter condition

deleteResult = collection.delete_one({"red" : 123, "green" : 223})

print("Number of documents deleted from the MongoDB collection:")

print(deleteResult.deleted_count)

# Print the collection after deleting a single record meeting the criteria

print("After deletion:");

for mongoDBdocument in collection.find():

print(mongoDBdocument)

Output:

Before deletion:

{'_id': ObjectId('5ab9fad002334a0303b029c1'), 'color1': 'red', 'color2': 'blue'}

{'_id': ObjectId('5ab9fb8302334a031cc2fc14'), 'red': 146, 'green': 46, 'blue': 246}

{'_id': ObjectId('5aba309f74d9af6fff2f2209'), 'red': 123.0, 'green': 223.0, 'blue': 23.0}

Number of documents deleted from the MongoDB collection:

After deletion:

{'_id': ObjectId('5ab9fad002334a0303b029c1'), 'color1': 'red', 'color2': 'blue'}

{'_id': ObjectId('5ab9fb8302334a031cc2fc14'), 'red': 146, 'green': 46, 'blue': 246}

Deleting multiple documents satisfying a filter condition:

To delete multiple documents from a MongoDB collection the db.collection.deletemany()method can be used.
db.collection.deletemany()can be passed with a JSON document specifying the filter condition. This method removes all the documents matching the specified filter condition.
If the filter condition is empty the method db.collection.deletemany()removes all the documents from the document collection.

Example:

# import the python driver for MongoDB

from pymongo import MongoClient

# Create a MongoDB client

mongoDBConnection = MongoClient('localhost', 27017)

# Get a collection instance

collection = mongoDBConnection.sample.orders

# Print the collection before deleting a single record meeting the criteria

print("Before deletion:");

for mongoDBdocument in collection.find():

print(mongoDBdocument)

# Delete all the order records which are in cancelled state

deleteResult = collection.delete_many({"Status" : "Cancelled"})

print("Number of documents deleted from the MongoDB collection:")

print(deleteResult.deleted_count)

# Print the collection after deleting a single record meeting the criteria

print("After deletion:");

for mongoDBdocument in collection.find():

print(mongoDBdocument)

Output:

Before deletion:

{'_id': ObjectId('5aba593174d9af6fff2f2213'), 'OrderId': '536728', 'Symbol': 'MSFT', 'Side': 'Buy', 'Qty': '100', 'Price': '91.95', 'Venue': 'NasdaqGS', 'Status': 'Ordered', 'TimeStamp': '1522161353'}

{'_id': ObjectId('5aba596374d9af6fff2f2216'), 'OrderId': '536821', 'Symbol': 'GOOG', 'Side': 'Sell', 'Qty': '50', 'Price': '1147.01', 'Venue': 'NasdaqGS', 'Status': 'Cancelled', 'TimeStamp': '1522161363'}

{'_id': ObjectId('5aba597274d9af6fff2f2217'), 'OrderId': '536841', 'Symbol': 'AMZN', 'Side': 'Sell', 'Qty': '50', 'Price': '1668.87', 'Venue': 'NasdaqGS', 'Status': 'Cancelled', 'TimeStamp': '1522161461'}

Number of documents deleted from the MongoDB collection:

After deletion: