Creating a schema and model

Schema

In order start adding collections and documents to our database, we use Mongoose’s schema structure. (This is specific to Mongoose and is not a structure that is a part of Mongo in general.)

We use a schema to define the shape of documents in a MongoDB collection. To do this we instantiate an instance of the Mongoose Schema class and set our properties:

Creating a schema

const courseSchema = new mongoose.Schema({
  name: { type: String, required: true, minlength: 5, maxlength: 255 },
  author: String,
  tags: [String],
  data: { type: Date, default: Date.now }, // if unspecified, entry will default to current date
  isPublished: Boolean,
});

This is similar to declaring a type or interface in TypeScript

Available data types

The following data types are available:

  • String
  • Number
  • Boolean
  • Array
  • Date
  • Buffer
  • ObjectID (for UUIDs)

Note that we set our validation criteria as the second property for each schema value. There is more info info on validation in a separate entry;

Models

Once we have established our schema we can then create a model of it. A model is basically a class representation of the interface we define in the schema:

const Course = mongoose.model("Course", courseSchema);

Now we can start adding specific courses as documents to our collection. We do this by referring to the model, i.e.

const course = new Course({
  name: "Node.js Course",
  author: "Ozzy Osbourne",
  tags: ["node", "backend"],
  isPublished: true,
});

Outcome

Having created a database, connected to it with Mongoose, and created a model we will see our collection reflected in Compass:

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