Table of Contents
What is the difference between update and save in MongoDB?
In MongoDB, the ‘update ()’ and ‘save ()’ methods are used to update the document into a collection. The ‘update ()’ method is used to update the values present in the existing document whereas ‘save ()’ method replaces the entire existing document with the new document which is passed in the ‘save ()’ method.
Can we update MongoDB?
MongoDB’s update() and save() methods are used to update document into a collection. The update() method updates the values in the existing document while the save() method replaces the existing document with the document passed in save() method.
How do I update entries in MongoDB?
The MongoDB shell provides the following methods to update documents in a collection:
- To update a single document, use db. collection. updateOne() .
- To update multiple documents, use db. collection. updateMany() .
- To replace a document, use db. collection. replaceOne() .
Does MongoDB update automatically?
No, there is no such thing (autoupdate) in MongoDB. It must be done with application or script.
What is the difference between insert and save in MongoDB?
But the main difference between ‘save’ and ‘insert’ command is that the ‘save’ command can insert or update a document whereas ‘insert’ only performs the insertion.
What is difference between find and findOne?
Difference between find() and findOne() methods in MongoDB? The findOne() returns first document if query matches otherwise returns null. The find() method does not return null, it returns a cursor. There is no document present in the above collection.
How do you update a document?
Select the document you want to edit by clicking the document name. On the Document Details page, click EDIT / UPDATE. You can see this button at the top right corner of the page only if you have Document Edit Permission. On the Edit Document page, make your changes.
What is Upsert MongoDB?
In MongoDB, upsert is an option that is used for update operation e.g. update(), findAndModify(), etc. Or in other words, upsert is a combination of update and insert (update + insert = upsert).
What is MapReduce in MongoDB?
As per the MongoDB documentation, Map-reduce is a data processing paradigm for condensing large volumes of data into useful aggregated results. MongoDB uses mapReduce command for map-reduce operations. MapReduce is generally used for processing large data sets.
What is the difference between findById and findOne?
Difference between findById() & findOne(): The main difference between these two methods is how MongoDB handles the undefined value of id. If you use findOne({ _id: undefined }) it will return arbitrary documents. However, mongoose translates findById(undefined) into findOne({ _id: null }).
What is updating document?
To update a document, you can upload a new document version or change the document’s name, description, or lock status. You can also update a document in TeamForge directly from one of the following Microsoft Office applications: Word. Excel.
What is the difference between find and findOne?
What is aggregation and indexing in MongoDB?
Aggregations operations process data records and return computed results. Aggregation operations group values from multiple documents together, and can perform a variety of operations on the grouped data to return a single result. In SQL count(*) and with group by is an equivalent of MongoDB aggregation.
Is findById faster than findOne?
Outside the context of your use case, findOne is likely insignificantly faster when provided valid ObjectIds, in the sense that passing an invalid ID through . findOne({ _id }) will not ensure _id is a valid ObjectId. However, given malformed ID’s, .
How do I update multiple files in MongoDB?
In MongoDB, you can update multiple documents in the collection using db. collection. updateMany() method.
- updateMany() method can be used in the multi-document transactions.
- When you update your documents the value of _id field in not change.
- It also adds new fields in the documents.
Can we change _ID in MongoDB?
You cannot update it. You’ll have to save the document using a new _id , and then remove the old document.