Update And Return Document In Mongodb

Question

I want to get updated documents. This is my original code and it succesfully updates but doesnt return the document.

collection.update({ \"code\": req.bo         


        

Answer 1

collection.update() will only report the number of documents that were affected to its own callback.

To retrieve the documents while modifying, you can use collection.findOneAndUpdate() instead (formerly .findAndModify()).

collection.findOneAndUpdate(
    { "code": req.body.code },
    { $set: req.body.updatedFields },
    { returnOriginal: false },
    function (err, documents) {
        res.send({ error: err, affected: documents });
        db.close();
    }
);

The returnOriginal option (or new with Mongoose) lets you specify which version of a found document (original [default] or updated) is passed to the callback.

---

Disclaimer: This answer currently refers to the Node.js Driver as of version 3.6. As new versions are released, check their documentation for possibly new deprecation warnings and recommended alternatives.

Answer 2

Checkout the WriteResult object:

http://docs.mongodb.org/manual/reference/method/db.collection.update/#writeresults-update

WriteResult result = collection.update({ "code": req.body.code },{$set:  req.body.updatedFields}, function(err, results) {
                    res.send({error: err, affected: results});
                    db.close();
                });

result should have something like:

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

If you want the updated results, do another query with the primary key.

Answer 3

The solution is to set: {returnOriginal: false}.

collection.findOneAndUpdate(
        whereObj,
        updateObj,
        {returnOriginal: false});

Answer 4

Could not find any way to update many and return the modified records in docs, so I made a workaround.

At least one fault that I can find with below method is, you would not be able to tell if document is modified or already had the value that you are using:

function findAndUpdateMany(filter, updateOptions) {
  return collection.find(filter).project({_id: 1}).toArray()
    .then(function(matchingIds) {
      filter = {_id: {$in: matchingIds}}
      return collection.updateMany(filter, updateOptions)
    }).then(function() {
      return collection.find(filter).toArray()
    })
}