MongoDB updateOne() Method

The updateOne() method in MongoDB updates the first document that matches a specified condition in a collection. It is used to change fields or values in a single matching document without affecting others.

Syntax

db.collection.updateOne(<filter>, <update>, {
   upsert: <boolean>,
   writeConcern: <document>,
   collation: <document>,
   arrayFilters: [<filterdocument1>, ...],
   hint: <document|string> // Available starting in MongoDB 4.2.1
})

• <filter>: Criteria to select the document to update.
• <update>: Modifications to apply (document or pipeline).
• upsert: false by default; true inserts a new document if none match.
• writeConcern: Overrides the default write concern.
• collation: Language-specific rules for string comparison.
• arrayFilters: Filters specifying which array elements to update.
• hint: Specifies which index to use for the operation.

Return value of updateOne()

This method returns a document that contains the following fields:

• matchedCount: This field contains the number of matched documents.
• modifiedCount: This field contains the number of modified documents.
• upsertedId: This field contains the _id for the upserted document.
• acknowledged: Indicates whether the write operation was acknowledged (true by default unless write concern is set to w: 0).

Examples of MongoDB updateOne() Method

Let’s go over a few examples to understand how updateOne() works in MongoDB. In the following examples, we are working with:

• Database: gfg
• Collection: student
• Document: Three documents contain name and age of the students.

Example 1: Update an Integer Value in the Document

Update the age of the student whose name is Alen.

Query:

db.student.updateOne({Name: "Alen"}, {$set:{age:25}})

Output:

Example 2: Update a String Value in the Document

Update the first matched name from Ron to Ryan (same data type).

Query:

db.student.updateOne({Name:"Ron"},{$set:{Name:"Ryan"}})

Output:

Example 3: Insert a new field in the document

Add a new field named class with the value 3 to the document where the student’s name is Kim.

Query:

db.student.updateOne({Name: "Kim"}, {$set:{class: 3}})

Output:

Example 4: Update using Update Operator Expressions

Update the first document where name is "Kim" to set age to 25:

Query:

db.student.updateOne({ name: "Kim" }, { $set: { age: 25 } })

Output:

Example 5: Update with Aggregation Pipeline

Increment the age of the first matched document where name is "Kim" using the aggregation pipeline.

Query:

db.student.updateOne({ name: "Kim" }, [{ $set: { age: { $add: ["$age", 1] } } }])

Output:

Example 6: Update with Upsert

Updating the document with name "Clevin" if it exists; otherwise, inserting a new document with name "Clevin" and age 28.

Query:

db.student.updateOne({ Name: "Clevin" }, { $set: { age: 28 } }, { upsert: true })

Output: