Updating Multiple Documents in MongoDB: The updateMany() Method

Learn how to efficiently modify multiple documents in MongoDB collections using the updateMany() method. This guide will cover the various update operators and techniques, allowing you to perform bulk updates on your data. Understand the benefits of using updateMany() over updateOne() for efficient data modification.

MongoDB: Update Multiple Documents using updateMany()

MongoDB provides two primary methods to update documents in a collection:

• db.collection.updateOne() - Modifies a single document.
• db.collection.updateMany() - Modifies multiple documents.

In most cases, updateMany() is preferred over updateOne() when you need to update multiple documents.

Syntax

The syntax for updateMany() is:

db.collection.updateMany(filter, update, options)
        

Parameters:

• filter: The selection criteria for the update, similar to the find() method.
• update: A document or pipeline that contains modifications to apply.
• options: Optional. Includes options for update behavior such as upsert, writeConcern, collation, etc.

Sample Data

Insert the following documents into the employees collection:

db.employees.insertMany([
    { _id: 1, firstName: "John", lastName: "King", email: "john.king@abc.com", salary: 5000 },
    { _id: 2, firstName: "Sachin", lastName: "T", email: "sachin.t@abc.com", salary: 8000 },
    { _id: 3, firstName: "James", lastName: "Bond", email: "jamesb@abc.com", salary: 7500 },
    { _id: 4, firstName: "Steve", lastName: "J", email: "steve.j@abc.com", salary: 7000 },
    { _id: 5, firstName: "Kapil", lastName: "D", email: "kapil.d@abc.com", salary: 4500 },
    { _id: 6, firstName: "Amitabh", lastName: "B", email: "amitabh.b@abc.com", salary: 7000 }
])
        

Examples

1. **Update Matching Documents**

Update the salary field for all documents where salary is 7000:

db.employees.updateMany({ salary: 7000 }, { $set: { salary: 8500 } })
        

Output:

{
  acknowledged: true,
  insertedId: null,
  matchedCount: 2,
  modifiedCount: 2,
  upsertedCount: 0
}
    

Check the updated documents:

db.employees.find()
        

Output:

[
  { _id: 1, firstName: 'John', lastName: 'King', email: 'john.king@abc.com', salary: 5000 },
  { _id: 2, firstName: 'Sachin', lastName: 'T', email: 'sachin.t@abc.com', salary: 8000 },
  { _id: 3, firstName: 'James', lastName: 'Bond', email: 'jamesb@abc.com', salary: 7500 },
  { _id: 4, firstName: 'Steve', lastName: 'J', email: 'steve.j@abc.com', salary: 8500 },
  { _id: 5, firstName: 'Kapil', lastName: 'D', email: 'kapil.d@abc.com', salary: 4500 },
  { _id: 6, firstName: 'Amitabh', lastName: 'B', email: 'amitabh.b@abc.com', salary: 8500 }
]
    

2. **Add a New Field**

Add the location field to documents with firstName: "Steve":

db.employees.updateMany({ firstName: "Steve" }, { $set: { location: "USA" } })
        

Output:

{
  acknowledged: true,
  insertedId: null,
  matchedCount: 1,
  modifiedCount: 1,
  upsertedCount: 0
}
    

Check the updated document:

db.employees.find({ firstName: "Steve" })
        

Output:

{ 
  _id: 4,
  firstName: "Steve",
  lastName: "J",
  email: "steve.j@abc.com",
  salary: 8500,
  location: "USA"
}
    

3. **Update All Documents**

Add the location field to all documents:

db.employees.updateMany({}, { $set: { location: "USA" } })
        

Output:

{
  acknowledged: true,
  insertedId: null,
  matchedCount: 6,
  modifiedCount: 6,
  upsertedCount: 0
}
    

4. **Use the $inc Operator**

Increase the salary by 500 for documents where salary is 8500:

db.employees.updateMany({ salary: 8500 }, { $inc: { salary: 500 } })
        

Output:

{
  acknowledged: true,
  insertedId: null,
  matchedCount: 2,
  modifiedCount: 2,
  upsertedCount: 0
}
    

5. **Update Multiple Fields**

Update the email and lastName fields for the document with _id: 2:

db.employees.updateMany({_id: 2}, { $set: { lastName: "Tendulkar", email: "sachin.tendulkar@abc.com" } })
        

Output:

{
  acknowledged: true,
  insertedId: null,
  matchedCount: 1,
  modifiedCount: 1,
  upsertedCount: 0
}
    

Check the updated document:

db.employees.find({_id: 2})
        

Output:

{ 
  _id: 2,
  firstName: "Sachin",
  lastName: "Tendulkar",
  email: "sachin.tendulkar@abc.com",
  salary: 8000
}
    

6. **Upsert - Add if Not Exist**

Add a new document if no document matches the filter:

db.employees.updateMany({ firstName: "Heer" }, { $set: { lastName: "Patel", salary: 2000 } }, { upsert: true })
        

Output:

{
  acknowledged: true,
  insertedId: ObjectId("6172a2e9ce7d5ca09d6ab082"),
  matchedCount: 0,
  modifiedCount: 0,
  upsertedCount: 1
}
    

Update Operators

Here are some common update operators you can use with updateOne() and updateMany():

For more details, refer to the MongoDB Update Operators documentation.