Schema

Learn model schemas with Mongoose Schema.

The data blueprint

In Mongoose you define the data shape by creating a blueprint. This blueprint specifies which fields exist, their types (String, Number, Date), and validation rules. This keeps documents consistent.

The blueprint is written as a JavaScript object. For example { name: String, age: Number } defines two fields. Mongoose automatically builds a data structure from this definition. You cannot create a model without a blueprint; so the blueprint is the foundation of Mongoose.

Field types

Each field in a blueprint takes a type. Common types: String (text), Number (number), Date (date), Boolean (logical), Buffer (binary). The type determines how Mongoose stores and validates the document.

A type can also take options: { type: String, required: true, default: "name" }. required: true means the field cannot be empty; default gives a fallback value. This enforces data integrity at the application layer.

Exercise Log the connection state

Import the mongoose module. Log mongoose.connection.readyState. (If not connected it is 0.)

Show example solution

const mongoose = require("mongoose");
console.log(mongoose.connection.readyState);

Test yourself

Complete the module name

const mongoose = require("____")

Show answer

const mongoose = require("mongoose")

What determines a field's type in a blueprint?
- A file name
- A JavaScript constructor (String, Number...)
- A network connection
- A port number
Show answer

A JavaScript constructor (String, Number...) — The type is given by JavaScript constructors like String, Number.
Match each piece to its role

String

Text
Number

Number
Date

Date
Boolean

Logical

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