How create a new array field with the aggregate framework

Question

I\'m starting to use mongoDb and I\'m stuck with a simple use case.

Let\'s say I\'ve got a collection \'aCollection\' with entries such as this:

Answer 1

You don't need the aggregation feature for this. A find, forEach, and insert is one potential approach:

db.aCollection.find().forEach( function(myDoc) {
  myDoc.geometry = {type: "Point", coordinates: [myDoc.lat, myDoc.long]};
  db.newCollection.insert(myDoc);
});

It calls an individual insert for each document, but is quick and dirty if you have a small collection.