Update a Collection to add a new Field with the value of another Field of same Collection in bulk mood

Question

I am bit new in mongoDB. Let's say I have a collection having a structure like this:

mycoll
{ 
    _id, 
    col1 -> NumberInt
}

And there are thousands of documents already in the collection. Now, I want to update every document of the collection to add a new field(i.e. col2) of NumberInt type whose value will be same as the value of field col1. Is there any way to do that in bulk mood not running the update command for each document? I am currently using mongoDB of version 4.4.1

Answer 1

You can use Mongo updateMany() Functionality.

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

Check this link for further detail, Update Many documentation