check if entry exists in mongodb

Question

I am wondering how I can check if an entry exists in mongodb. example :

I have this schema :

const AuthorSchema = new Schema({
    name : { type : String,  required : true},
    books: [BookSchema]
});

If the Author i am trying to add already exists I would like to still add the book to the existing author , but I dont want to create a duplicate of author.

Pseudo code is fine, as long as I get the Idea of the flow. Any posts or blog articles are fine as long as they describe the problem i am having.

Did you take a look at [upsert command](https://docs.mongodb.com/manual/reference/method/Bulk.find.upsert/index.html) already? — gmauch, Mar 25 '20 at 13:05

score 0 · Answer 1 · answered Mar 25 '20 at 13:43

The following are the links that may help you to solve your problem:

1) https://docs.mongodb.com/manual/reference/operator/query/exists/

2) https://blog.serverdensity.com/checking-if-a-document-exists-mongodb-slow-findone-vs-find/

3) How to query MongoDB to test if an item exists?

4) https://www.freecodecamp.org/forum/t/mongodb-node-check-if-a-document-within-a-collection-has-a-specific-field/97623

check if entry exists in mongodb

1 Answers1