How to update document with marks value in MongoDB for student David

To update a specific document's marks value for student David in MongoDB, you can use the forEach() method to traverse the collection and find the student, then update their marks using the $set operator.

Syntax

db.collection.find({Name: "StudentName"}).forEach(function(doc) {
    db.collection.update({_id: doc._id}, {$set: {Marks: newValue}});
});

Sample Data

Let us create a collection with student documents ?

db.demo634.insertMany([
    {Name: "Chris", Marks: 76},
    {Name: "Bob", Marks: 67},
    {Name: "David", Marks: 37}
]);

{
   "acknowledged" : true,
   "insertedIds" : [
      ObjectId("5e9c0ea66c954c74be91e6c9"),
      ObjectId("5e9c0ead6c954c74be91e6ca"),
      ObjectId("5e9c0eb76c954c74be91e6cb")
   ]
}

Display all documents from the collection ?

db.demo634.find();

{ "_id" : ObjectId("5e9c0ea66c954c74be91e6c9"), "Name" : "Chris", "Marks" : 76 }
{ "_id" : ObjectId("5e9c0ead6c954c74be91e6ca"), "Name" : "Bob", "Marks" : 67 }
{ "_id" : ObjectId("5e9c0eb76c954c74be91e6cb"), "Name" : "David", "Marks" : 37 }

Example: Update David's Marks Using forEach()

Update David's marks from 37 to 98 using forEach() traversal ?

db.demo634.find({Name: "David"}).forEach(function(d) {
    db.demo634.update({_id: d._id}, {$set: {Marks: 98}});
});

Verify Result

Display all documents to confirm the update ?

db.demo634.find();

{ "_id" : ObjectId("5e9c0ea66c954c74be91e6c9"), "Name" : "Chris", "Marks" : 76 }
{ "_id" : ObjectId("5e9c0ead6c954c74be91e6ca"), "Name" : "Bob", "Marks" : 67 }
{ "_id" : ObjectId("5e9c0eb76c954c74be91e6cb"), "Name" : "David", "Marks" : 98 }

Alternative: Direct Update Method

You can also update directly without forEach() for better performance ?

db.demo634.updateOne({Name: "David"}, {$set: {Marks: 98}});

Conclusion

The forEach() method allows you to traverse and update documents by finding specific criteria. However, for simple updates, using updateOne() directly is more efficient and recommended.