MongoDB – Update() Method

The update() method in MongoDB updates a document or multiple documents in the collection. When the document is updated the _id field remains unchanged.

This method can be used for a single updating of documents as well as multiple documents. By default, the db.collection.update() method updates a single document. To update all documents that match the given query. Include the option “multi: true“.

Note: In MongoDB, the update() method has been deprecated in favor of using updateOne() or updateMany() depending on your specific use case.

MongoDB Update() Method Syntax

db.COLLECTION_NAME.update({SELECTION_CRITERIA}, {$set:{UPDATED_DATA}}, {
     upsert: <boolean>,
     multi: <boolean>,
     writeConcern: <document>,
     collation: <document>,
     arrayFilters: [ <filterdocument1>, ... ],
     hint:  <document|string>        
   })

Parameters:

• SELECTION_CRITERIA: The selection filter for the update.
• $set: Keyword to update the following specify document value.
• UPDATED_DATA: New value that will replace the existing document.

Optional Parameters:

• Upsert: When it is true it will make a new document in the collection when no document matches the given condition in the update method. The default value of this parameter is false.
• multi: When it is true the update method update all the documents that meet the query condition. Otherwise, it will update only one document. The default value of this parameter is false.
• writeConcern: It is only used when you do not want to use the default write concern. The type of this parameter is a document.
• Collation: It specifies the use of the collation for operations. It allows users to specify the language-specific rules for string comparison like rules for lettercase and accent marks. The type of this parameter is a document.
• arrayFilters: It is an array of filter documents that indicates which array elements to modify for an update operation on an array field. The type of this parameter is an array.
• hint: It is a document or field that specifies the index to use to support the filter. It can take an index specification document or the index name string and if you specify an index that does not exist, then it will give an error.

MongoDB Update Method Examples

In the following examples, we are working with:

• Database: gfg
• Collections: student
• Document: Three documents contains name and the age of the students

Example 1:

Update the name of the document whose name key has avi value to hello world.

db.student.update({name:"avi"},{$set:{name:"helloword"}})

Here, the first parameter is the document whose value to be changed {name:”avi”} and the second parameter is set keyword means to set(update) the following matched key value with the older key value.

Note: The value of the key must be of the same datatype that was defined in the collection.

Example 2:

Update the age of the document whose name is prachi to 20.

db.student.update({name:"prachi"},{$set:{age:20}}

Here, the first parameter is the document whose value to be changed {name:”prachi”} and the second parameter is set keyword means to set(update) the value of the age field to 20.

Conclusion

The update method in MongoDB was used to update values in the MongoDB database. It updates documents in a collection. This method has now been deprecated and MongoDB has introduced new methods to update documents in a collection – updateOne() and updateMany().