Incrementing a day to a Date in MongoDB

Question

How can I increment a date by 7 days in a document without having to manually set the date?

Collection Data:
{
    "_id" : ObjectId("5e302f83edd1fd00125abbf9"),
    "dateTransferred" : 2020-01-26T00:00:00.000+00:00
}

I can easily update the collection by using:

db.data.updateMany(
  {},
  {
    "$set": { "dateTransferred": new ISODate("2020-02-03T03:34:54Z") }
  }
)

Is there a way I can update it dynamically (Similar to DateAdd)

Answer 1

Yes, in MongoDB 4.2+ you can update it like this:

db.col.updateOne(
   { "_id": ObjectId("5e302f83edd1fd00125abbf9") },
   [
      { $set: { dateTransferred: { $add: ["$dateTransferred", 1000 * 60 * 60 * 24] } } }
   ]
)

Of course, if you like to update all documents then it would be

db.col.updateMany(
   {},
   [
      { $set: { dateTransferred: { $add: ["$dateTransferred", 1000 * 60 * 60 * 24] } } }
   ]
)

Answer 2

No, you can not access values of record that is being updated using this simple notation.

You might want to try using the aggregation pipeline (limited to mongodb 4.2+) as described here: https://docs.mongodb.com/manual/reference/method/db.collection.update/#update-with-aggregation-pipeline

So far, I haven't tried this myself, but looks promising ;-)