Mongodb duplicate errorr - node.js

Question

db.collection("resource").update({name: name}, {
name: name,
type: type
}, {
upsert: true
}
I differentiate documents by their names. I do not add document if it exists with the same. But I want to warn user by saying "It already exists, operation failed" How can I achieve it?

Answer 1

It sounds like you want to insert documents, not update or insert documents.
1: Add unique index on resource.name ahead of time.
db.resouces.createIndex({ name: 1 }, { unique: true })
Important: do this once, not on every request.
See mongodb create index docs.
2: Use insert instead of update + upsert.
It sounds like you want to actually insert a document, and get an error if there is a duplicate key.
db.resources.insert({ name: "AJ" }) // ok
db.resources.insert({ name: "AJ" }) // error!
You will get a duplicate key error on the second insert. Error code 11000.
See mongodb docs on insert.
3: Use promise-try-catch in javascript.
The code to do error checking looks like:
var db = require("mongojs")(DATABASE_URL, [ "resources" ])
var duplicateKey = function (err) {
return err.code == "11000"
}
db.resources.insert({ name: name })
.then(function () {
// success!
})
.catch(duplicateKey, function () {
// sorry! name is taken
})