What is Mongoose model explain with example?

A Mongoose model is a wrapper on the Mongoose schema. A Mongoose schema defines the structure of the document, default values, validators, etc., whereas a Mongoose model provides an interface to the database for creating, querying, updating, deleting records, etc.

What is ref in Mongoose model?

The ref option is what tells Mongoose which model to use during population, in our case the Story model. All _id s we store here must be document _id s from the Story model. Note: ObjectId , Number , String , and Buffer are valid for use as refs.

Is Mongoose model a class?

Mongoose allows creating schemas from ES6 classes. The loadClass() function lets you pull in methods, statics, and virtuals from an ES6 class. A class method maps to a schema method, a static method maps to a schema static, and getters/setters map to virtuals. View more jobs!

What does model find return in Mongoose?

The Model. find() function returns an instance of Mongoose’s Query class. The Query class represents a raw CRUD operation that you may send to MongoDB. It provides a chainable interface for building up more sophisticated queries. You don’t instantiate a Query directly, Customer.

Why is Mongoose used?

Mongoose is a Node. js-based Object Data Modeling (ODM) library for MongoDB. It is akin to an Object Relational Mapper (ORM) such as SQLAlchemy for traditional SQL databases. The problem that Mongoose aims to solve is allowing developers to enforce a specific schema at the application layer.

What are parameters for Mongoose model?

Parameters: This function accepts the following two parameters: Collection name: It is the name of the collection. Collection Schema: It is the schema of the collection.

What is Mongoose types ObjectId?

Types. ObjectId . A SchemaType is just a configuration object for Mongoose. An instance of the mongoose. ObjectId SchemaType doesn’t actually create MongoDB ObjectIds, it is just a configuration for a path in a schema.

What is discriminator in Mongoose?

Discriminators are a schema inheritance mechanism. They enable you to have multiple models with overlapping schemas on top of the same underlying MongoDB collection. Suppose you wanted to track different types of events in a single collection.

Is Mongoose query a promise?

Mongoose queries are not promises. They have a . then() function for co and async/await as a convenience.

What is select in mongoose?

select() is a method of Mongoose that is used to select document fields that are to be returned in the query result. It is used to include or exclude document fields that are returned from a Mongoose query. The select() method performs what is called query projection.

Should I use MongoDB or mongoose?

On the downside, learning mongoose can take some time, and has some limitations in handling schemas that are quite complex. However, if your collection schema is unpredictable, or you want a Mongo-shell like experience inside Node. js, then go ahead and use the mongodb driver. It is the simplest to pick up.

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