MongoDB Documentation, Release 3.0.4 Remove Isolation of Write Operations Additional Methods In MongoDB, the db.collection.remove() method deletes documents from a collection. The db.collection.remove() method accepts a query criteria to determine which documents to remove. The following diagram highlights the components of a MongoDB remove operation: The following diagram shows the same query in SQL: This delete operation on the users collection removes all documents that match the criteria of status equal to D . Example For more information, see db.collection.remove() method and Remove Documents (page 106). Remove Behavior By default, db.collection.remove() method removes all documents that match its query. However, the method can accept a flag to limit the delete operation to a single document. The modification of a single document is always atomic, even if the write operation modifies multiple embedded documents within that document. No other operations are atomic. If a write operation modifies multiple documents, the operation as a whole is not atomic, and other operations may in- terleave. You can, however, attempt to isolate a write operation that affects multiple documents using the isolation operator . For more information Atomicity and Transactions (page 80). The db.collection.save() method can either update an existing document or insert a document if the docu- ment cannot be found by the _id field. See db.collection.save() for more information and examples. MongoDB also provides methods to perform write operations in bulk. See Bulk() for more information. 3.2. MongoDB CRUD Concepts 77 db.users.remove( { status: "D" } )