Update in MongoDB

Update Document

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().

The examples on this page reference the Atlas sample dataset

Update Operator Syntax

To update a document, MongoDB provides update operators, such as $set, to modify field values.

Update a Single Document

Use the db.collection.updateOne() method to update the first document that matches a specified filter.

To update the first document in the sample_mflix.movies collection where title equals "Tag":

use sample_mflix

db.movies.updateOne( { title: "Tag" },

{

$set: {

plot: "One month every year, five highly competitive friends

hit the ground running for a no-holds-barred game of tag"

}

{ $currentDate: { lastUpdated: true } }

})

The update operation:

• Uses the $set operator to update the value of the plot field for the movie Tag.

• Uses the $currentDate operator to update the value of the lastUpdated field to the current date. If lastUpdated field does not exist, $currentDate will create the field. See $currentDate for details.

Update Multiple Documents

Use the db.collection.updateMany() to update all documents that match a specified filter.

To update all documents in the sample_airbnb.listingsAndReviews collection to update where security_deposit is less than 100:

use sample_airbnb

db.listingsAndReviews.updateMany(

{ security_deposit: { $lt: 100 } },

{

$set: { security_deposit: 100, minimum_nights: 1 }

}

)

he update operation uses the $set operator to update the value of the security_deposit field to 100 and the value of the minimum_nights field to 1.

Replace a Document

To replace the entire content of a document except for the _id field, pass an entirely new document as the second argument to db.collection.replaceOne().

When replacing a document, the replacement document must contain only field/value pairs. Do not include update operators expressions.

The replacement document can have different fields from the original document. In the replacement document, you can omit the _id field since the _id field is immutable; however, if you do include the _id field, it must have the same value as the current value.

To replace the first document from the sample_analytics.accounts collection where account_id: 371138:

db.accounts.replaceOne(

{ account_id: 371138 },

{ account_id: 893421, limit: 5000, products: [ "Investment", "Brokerage" ] }

)

Run the following command to read your updated document:

db.accounts.findOne( { account_id: 893421 } )