How do I maintain data types when copying document? - mongodb

Question

I need to make a change to use a generated ObjectId instead of String I was using but the field data type changes from Int to Double.
For example say we have a document
{_id: "Product Name", count: 415 }
Now I want to create a document
{_id: "some object id", name: "Product Name", count: 415 }
I am using similar code below but it makes the count a Double.
var cursor = db.products.find()
cursor.forEach(function(item)
{
var old_id= item._id;
item.name = old_id;
delete item._id;
db.products.insert(item);
db.products.remove({_id:old_id});
});
I can add this in the loop: item.count = NumberInt( item.count) to make sure it's an Int but
I really don't want to do this for each field that I have.
Is there anyway to do this without manually having to cast them? I don't understand why it takes an Int and turns it into a Double. I know Double is the default but the fields that I am working with are already Integers.

Answer 1

Well if I understand you, your documents look like this:
{ "_id" : "Apple", "count" : 187 }
{ "_id" : "Google", "count" : 123 }
{ "_id" : "Amazon", "count" : 325 }
{ "_id" : "Oracle", "count" : 566 }
You can use the Bulk Api to update your collection.
var bulk = db.collection.initializeUnorderedBulkOp();
Var count = 0;
db.collection.aggregate([{ $project: { '_id': 0, 'name': '$_id', 'count': 1 }}]).forEach(function(doc){
bulk.find({'_id': doc.name}).remove();
bulk.insert(doc);
count++;
if (count % 1000 == 0){
// Execute per 1000 operations and re-init.
bulk.execute();
bulk = db.collection.initializeUnorderedBulkOp();
}})
// Clean up queues
if (count % 1000 != 0){
bulk.execute();
}
Then:
db.collection.find()
Yields the following documents:
{ "_id" : ObjectId("55a7e2c7eb68594275546c7c"), "count" : 187, "name" : "Apple" }
{ "_id" : ObjectId("55a7e2c7eb68594275546c7d"), "count" : 123, "name" : "Google" }
{ "_id" : ObjectId("55a7e2c7eb68594275546c7e"), "count" : 325, "name" : "Amazon" }
{ "_id" : ObjectId("55a7e2c7eb68594275546c7f"), "count" : 566, "name" : "Oracle" }
Is there anyway to do this without manually having to cast them? I don't understand why it takes an Int and turns it into a Double. I know Double is the default but the fields that I am working with are already Integers.
You really don't need to worry about that if you are using the shell but as pointed out in the comment you can always use a language with native support for integers to preserve the data type.