How to create in mongoose if not exists but not update

Question

I've only found ways to create OR update a document. I need to create if not exists but do nothing if it already exists. How to do it in mongoose?

Please note that findOneAndUpdate won't work, because if it fins the document, it updates it! I don't want that.

UPDATE:

I just want to create a variable called order_number that can be incremented. However, to increment, I must make sure the document exists. However, I cannot update its value in case it exists.

I tried:

let r = await OrderNumber.findOneAndUpdate({ unique: 0 }, { unique: 0, order_number: 0 }, { upsert: true });

It successfully creates when it does not exist, but always updates order_number to 0. I don't want this to happen.

Does this answer your question? [How do I update/upsert a document in Mongoose?](https://stackoverflow.com/questions/7267102/how-do-i-update-upsert-a-document-in-mongoose) — SuleymanSah, Jan 15 '20 at 19:30
Check this [answer](https://stackoverflow.com/a/24711713/11717458) — SuleymanSah, Jan 15 '20 at 19:31
@SuleymanSah the problem with upsert and findOneAndUpdate is that, if it already exists, it updates. I don't want to do that. I want to just create a new document if one does not exist. But never update. — Guerlando OCs, Jan 15 '20 at 21:37
@GuerlandoOCs : Can you give me a sample doc & required o/p..I wanted to check how you docs are & what is your filter query, maybe you need not to do `.findOneAndUpdate`.. — whoami - fakeFaceTrueSoul, Jan 15 '20 at 22:25
@GuerlandoOCs : So all you need to do is if no document with `{unique : 0}` then you need to insert a new doc with `{ unique: 0, order_number: 0 }` ? — whoami - fakeFaceTrueSoul, Jan 15 '20 at 22:56
@srinivasy yes, and `unique` was just a way to locate this document — Guerlando OCs, Jan 15 '20 at 23:05
@GuerlandoOCs : Hey only thing you could is to do it in two DB calls, as in general inserts doesn't have any filters unless `updates` are used.. — whoami - fakeFaceTrueSoul, Jan 15 '20 at 23:28

score 2 · Accepted Answer · answered Jan 15 '20 at 23:33

As only way I've found it via two DB calls as in general inserts doesn't have any filters unless findOneAnd* or upsert on updates are used - which we're not looking at. Then only option is to make two calls, here is basic code, please wrap those in proper function & try/catch to add error handling :

const mongoose = require('mongoose')
const Schema = mongoose.Schema;

const orderNumberSchema = new Schema({
    any: {}
}, {
    strict: false
});

const OrderNumber = mongoose.model('order_number', orderNumberSchema, 'order_number');

let resp = await OrderNumber.findOne({ unique: 0 });

if (!resp) {
    let orderNumberObj = new OrderNumber({ unique: 0, order_number: 0 })
    let r = await orderNumberObj.save();
}

How to create in mongoose if not exists but not update

1 Answers1