16.Update Methods-官方文档摘录

这里没什么好说的，直接贴文了

MongoDB provides the following methods for updating documents in a collection:

db.collection.updateOne()	Updates at most a single document that match a specified filter even though multiple documents may match the specified filter. New in version 3.2.
db.collection.updateMany()	Update all documents that match a specified filter. New in version 3.2.
db.collection.replaceOne()	Replaces at most a single document that match a specified filter even though multiple documents may match the specified filter. New in version 3.2.
db.collection.update()	Either updates or replaces a single document that match a specified filter or updates all documents that match a specified filter. By default, the db.collection.update() method updates a singledocument. To update multiple documents, use the multi option.

Additional Methods

The following methods can also update documents from a collection:

• db.collection.findOneAndReplace().
• db.collection.findOneAndUpdate().
• db.collection.findAndModify().
• db.collection.save().
• db.collection.bulkWrite().

See the individual reference pages for the methods for more information and examples.