Remove one or multiple documents from MongoDB collection
n = remove(conn,collection,mongoquery)
Connect to MongoDB and remove documents from a collection. Specify a MongoDB query to determine which documents to remove. Here, the collection represents employee data.
Create a MongoDB connection to the database mongotest. Here, the database server dbtb01 hosts this database using port number 27017.
server = "dbtb01"; port = 27017; dbname = "mongotest"; conn = mongo(server,port,dbname)
conn =
mongo with properties:
Database: 'mongotest'
UserName: ''
Server: {'dbtb01'}
Port: 27017
CollectionNames: {'airlinesmall', 'employee', 'largedata' ... and 3 more}
TotalDocuments: 23485919conn is the
mongo object that contains the MongoDB connection. The object properties contain information about the connection and the
database.
The database name is mongotest.
The user name is blank.
The database server is dbtb01.
The port number is 27017.
This database contains six document collections. The first three collection names are
airlinesmall, employee, and
largedata.
This database contains 23,485,919 documents.
Verify the MongoDB connection.
isopen(conn)
ans = logical 1
The database connection is successful because the isopen function returns 1. Otherwise, the database connection is closed.
Create a MongoDB query to identify documents to remove. Here, specify the
employee collection. Create the MongoDB query to identify documents in the Sales department.
collection = "employee"; mongoquery = '{"department":"Sales"}';
Remove documents using the MongoDB query. The remove function removes six
documents from the collection.
n = remove(conn,collection,mongoquery)
n =
6Close the MongoDB connection.
close(conn)
Connect to MongoDB and remove all documents from a collection.
Create a MongoDB connection to the database mongotest. Here, the database server dbtb01 hosts this database using port number 27017.
server = "dbtb01"; port = 27017; dbname = "mongotest"; conn = mongo(server,port,dbname)
conn =
mongo with properties:
Database: 'mongotest'
UserName: ''
Server: {'dbtb01'}
Port: 27017
CollectionNames: {'airlinesmall', 'employee', 'largedata' ... and 3 more}
TotalDocuments: 23485919conn is the
mongo object that contains the MongoDB connection. The object properties contain information about the connection and the
database.
The database name is mongotest.
The user name is blank.
The database server is dbtb01.
The port number is 27017.
This database contains six document collections. The first three collection names are
airlinesmall, employee, and
largedata.
This database contains 23,485,919 documents.
Verify the MongoDB connection.
isopen(conn)
ans = logical 1
The database connection is successful because the isopen function returns 1. Otherwise, the database connection is closed.
Remove all documents from the employee collection. Use
an empty MongoDB query to specify removing all documents. The
remove function removes three documents from the
collection.
collection = "employee"; n = remove(conn,collection,"{}")
n =
3Close the MongoDB connection.
close(conn)
conn — MongoDB connectionmongo objectMongoDB connection, specified as a mongo object.
collection — Collection nameCollection name, specified as a string scalar.
Example: "taxidata"
Data Types: string
mongoquery — MongoDB queryMongoDB query, specified as a string scalar or character vector. Specify a JSON-style string to query the database.
Example: '{"department":"Sales"}' queries the database for documents where
the department field is equal to
Sales.
Example: '{salary: {$gt: 90000}}' queries the database for documents where
the value of the salary field is greater than
90000.
Data Types: char | string
n — Number of documents removedNumber of documents removed from a collection in the database, returned as a numeric scalar.