node.js - Why does mongoose use schema when mongodb's benefit is supposed to be that it's schema-less?

Question

I am a super newbie to mongodb. I am using mongoose to access mongodb from node.js, and know how to get things to work, but I don't think I understand why it works the way it does.

Most importantly, I don't understand why mongoose has 'schema' when one of the standout features of mongodb is that it doesn't have schema. Could someone enlighten me? thank you.

Answer 1

Data without a schema is useless. You get a document from MongoDB, what do you do with it? Read some fields? You need to know the names, types and meanings of those fields. That’s a schema.

When people say that MongoDB “has no schema”, they really mean that it does not enforce schema the way SQL databases do. MongoDB pushes schema concerns up to your application level, where you can handle them more flexibly. For example, in order to add a new field to your documents, you don’t need to do an all-or-nothing ALTER on your collection—potentially millions of entries. You just add that field to your ODM (Mongoose) schema and you’re done.