Database & ORM

Welcome to Module 4! Up until now, our API has been “stateless” or using in-memory mock data. If we restarted the server, our data would disappear.

In this module, we are going to give our application a memory. We will persist data using a real database so that our users and tasks are saved permanently.

Learning Objectives

By the end of this module, you will be able to:

• Design a relational database schema
• Use Drizzle ORM to interact with your database type-safely
• Manage database migrations with Cloudflare D1

The Tech Stack

We will be using a powerful modern stack for our data layer:

1. Cloudflare D1: A serverless SQL database designed to run on the edge.
2. Drizzle ORM: A TypeScript ORM that is lightweight, type-safe, and developer-friendly.

What is Cloudflare D1?

D1 is Cloudflare’s native serverless SQL database. It’s built on SQLite, which means:

• It’s incredibly fast.
• It supports standard SQL.
• It runs globally, close to your users (on the “edge”).

Unlike traditional databases that require you to manage servers, connections, and scaling, D1 is fully managed and serverless.

What is Drizzle ORM?

Drizzle is an Object Relational Mapper (ORM). It allows us to interact with our database using TypeScript code instead of writing raw SQL strings.

Why we love Drizzle:

• Type Safety: It knows your schema. If you try to access a column that doesn’t exist, your code won’t compile.
• Performance: It has zero dependencies at runtime and adds almost no overhead.
• Great DX: It feels like writing SQL, but with the power of TypeScript.

SQL Refresher

Before we dive into the code, let’s quickly review some basic SQL concepts. D1 is based on SQLite, so standard SQL applies.

Tables

Data is stored in tables. Think of a table like a spreadsheet.

• Columns: Define the type of data (e.g., id, name, email).
• Rows: The actual data entries.

Basic Commands

CREATE TABLE Creates a new table structure.

CREATE TABLE users (
  id INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  email TEXT UNIQUE
);

INSERT Adds new rows to a table.

INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');

SELECT Retrieves data from a table.

SELECT * FROM users WHERE name = 'Alice';

In the next section, we will see how to define these structures using Drizzle in TypeScript!