You can delete documents in a collection using the remove() method of MongoDB. This method accepts two optional parameters −

• deletion criteria specifying the condition to delete documents.

• just one, if you pass true or 1 as second parameter, then only one document will be deleted.

Syntax

Following is the syntax of the remove() method −

>db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)

Example

Assume we have created a collection and inserted 5 documents into it as shown below −

> use testDB
switched to db testDB
> db.createCollection("myColl")
{ "ok" : 1 }
> data = [
   ... {"_id": "1001", "name": "Ram", "age": "26", "city": "Hyderabad"},
   ... {"_id": "1002", "name": "Rahim", "age": 27, "city": "Bangalore"},
   ... {"_id": "1003", "name": "Robert", "age": 28, "city": "Mumbai"},
   ... {"_id": "1004", "name": "Romeo", "age": 25, "city": "Pune"},
   ... {"_id": "1005", "name": "Sarmista", "age": 23, "city": "Delhi"},
   ... {"_id": "1006", "name": "Rasajna", "age": 26, "city": "Chennai"}
]
> db.sample.insert(data)
BulkWriteResult({
   "writeErrors" : [ ],
   "writeConcernErrors" : [ ],
   "nInserted" : 6,
   "nUpserted" : 0,
   "nMatched" : 0,
   "nModified" : 0,
   "nRemoved" : 0,
   "upserted" : [ ]
})

Following query deletes the document(s) of the collection which have name value as Sarmista.

> db.sample.remove({"name": "Sarmista"})
WriteResult({ "nRemoved" : 1 })
> db.sample.find()
{ "_id" : "1001", "name" : "Ram", "age" : "26", "city" : "Hyderabad" }
{ "_id" : "1002", "name" : "Rahim", "age" : 27, "city" : "Bangalore" }
{ "_id" : "1003", "name" : "Robert", "age" : 28, "city" : "Mumbai" }
{ "_id" : "1004", "name" : "Romeo", "age" : 25, "city" : "Pune" }
{ "_id" : "1006", "name" : "Rasajna", "age" : 26, "city" : "Chennai" }

If you invoke remove() method without passing deletion criteria, all the documents in the collection will be deleted.

> db.sample.remove({})
WriteResult({ "nRemoved" : 5 })
> db.sample.find()

Deleting documents using python

To delete documents from a collection of MangoDB, you can delete documents from a collections using the methods delete_one() and delete_many() methods.

These methods accept a query object specifying the condition for deleting documents.

The detele_one() method deletes a single document, in case of a match. If no query is specified this method deletes the first document in the collection.

Example

Following python example deletes the document in the collection which has id value as 1006.

from pymongo import MongoClient

#Creating a pymongo client
client = MongoClient(''localhost'', 27017)

#Getting the database instance
db = client[''lpaksgf'']

#Creating a collection
coll = db[''example'']

#Inserting document into a collection
data = [
   {"_id": "1001", "name": "Ram", "age": "26", "city": "Hyderabad"},
   {"_id": "1002", "name": "Rahim", "age": "27", "city": "Bangalore"},
   {"_id": "1003", "name": "Robert", "age": "28", "city": "Mumbai"},
   {"_id": "1004", "name": "Romeo", "age": 25, "city": "Pune"},
   {"_id": "1005", "name": "Sarmista", "age": 23, "city": "Delhi"},
   {"_id": "1006", "name": "Rasajna", "age": 26, "city": "Chennai"}
]
res = coll.insert_many(data)
print("Data inserted ......")

#Deleting one document
coll.delete_one({"_id" : "1006"})

#Retrieving all the records using the find() method
print("Documents in the collection after update operation: ")

for doc2 in coll.find():
   print(doc2)

Output

Data inserted ......
Documents in the collection after update operation:
{''_id'': ''1001'', ''name'': ''Ram'', ''age'': ''26'', ''city'': ''Hyderabad''}
{''_id'': ''1002'', ''name'': ''Rahim'', ''age'': ''27'', ''city'': ''Bangalore''}
{''_id'': ''1003'', ''name'': ''Robert'', ''age'': ''28'', ''city'': ''Mumbai''}
{''_id'': ''1004'', ''name'': ''Romeo'', ''age'': 25, ''city'': ''Pune''}
{''_id'': ''1005'', ''name'': ''Sarmista'', ''age'': 23, ''city'': ''Delhi''}

Similarly, the delete_many() method of pymongo deletes all the documents that satisfies the specified condition.

Example

Following example deletes all the documents in the collection whose age value is greater than 26 −

from pymongo import MongoClient

#Creating a pymongo client
client = MongoClient(''localhost'', 27017)

#Getting the database instance
db = client[''sampleDB'']

#Creating a collection
coll = db[''example'']

#Inserting document into a collection
data = [
   {"_id": "1001", "name": "Ram", "age": "26", "city": "Hyderabad"},
   {"_id": "1002", "name": "Rahim", "age": "27", "city": "Bangalore"},
   {"_id": "1003", "name": "Robert", "age": "28", "city": "Mumbai"},
   {"_id": "1004", "name": "Romeo", "age": "25", "city": "Pune"},
   {"_id": "1005", "name": "Sarmista", "age": "23", "city": "Delhi"},
   {"_id": "1006", "name": "Rasajna", "age": "26", "city": "Chennai"}
]
res = coll.insert_many(data)
print("Data inserted ......")

#Deleting multiple documents
coll.delete_many({"age":{"$gt":"26"}})

#Retrieving all the records using the find() method
print("Documents in the collection after update operation: ")

for doc2 in coll.find():
   print(doc2)

Output

Data inserted ......
Documents in the collection after update operation:
{''_id'': ''1001'', ''name'': ''Ram'', ''age'': ''26'', ''city'': ''Hyderabad''}
{''_id'': ''1004'', ''name'': ''Romeo'', ''age'': ''25'', ''city'': ''Pune''}
{''_id'': ''1005'', ''name'': ''Sarmista'', ''age'': ''23'', ''city'': ''Delhi''}
{''_id'': ''1006'', ''name'': ''Rasajna'', ''age'': ''26'', ''city'': ''Chennai''}

If you invoke the delete_many() method without passing any query, this method deletes all the documents in the collection.

coll.delete_many({})