D1 Database

Cloudflare D1 is a serverless SQLite database that runs at the edge. Accessed via getDB() inside server functions.

Table schema

PRAGMA table_info('notes')

The notes table is created automatically on first load via CREATE TABLE IF NOT EXISTS. Here's the live schema from D1.

Column	Type	PK	NOT NULL
id	INTEGER	yes
title	TEXT		yes
body	TEXT		yes
created_at	TEXT		yes

0 rows in the database.

Create a note

INSERT INTO notes (title, body) VALUES (?, ?)

Uses a POST server function with input validation. The data is bound with parameterized queries to prevent SQL injection.

const createNote = createServerFn({ method: 'POST' })
  .inputValidator((data: { title: string; body: string }) => {
    if (!data.title.trim()) throw new Error('Title is required')
    return data
  })
  .handler(async ({ data }) => {
    const db = getDB()
    const result = await db
      .prepare('INSERT INTO notes (title, body) VALUES (?, ?)')
      .bind(data.title, data.body)
      .run()
    return { id: result.meta.last_row_id }
  })

Notes from D1

SELECT * FROM notes ORDER BY id DESC

Loaded via the route loader on first render (SSR), refreshed client-side via router.invalidate(). Each row has a delete button that calls a POST server function.

No notes yet. Create one above.

Accessing D1 via getDB()

src/lib/env.ts

The env helper wraps the cloudflare:workers import and provides typed access to all bindings — D1, R2, KV, etc. Import getDB() in any server function.

// src/lib/env.ts
import { env } from 'cloudflare:workers'

export function getEnv(): Env {
  return env as Env
}

export function getDB(): D1Database {
  return getEnv().DB
}

// In any server function
import { getDB } from '~/lib/env'

const myServerFn = createServerFn().handler(async () => {
  const db = getDB()
  const { results } = await db
    .prepare('SELECT * FROM notes')
    .all()
  return results
})

The Env type is auto-generated by wrangler types into worker-configuration.d.ts. Add bindings to wrangler.jsonc, run wrangler types, and the types update.

Setup checklist

wrangler.jsonc + wrangler types

Steps to add D1 to a new project.

Create the database
```
wrangler d1 create my-db
```

Add the binding to wrangler.jsonc

"d1_databases": [{
  "binding": "DB",
  "database_name": "my-db",
  "database_id": "..."
}]

Regenerate types
```
wrangler types
```

Use getDB() in server functions

const db = getDB()
await db.prepare('SELECT 1').run()

Migrations: For production apps, use wrangler d1 migrations create and wrangler d1 migrations apply instead of CREATE TABLE IF NOT EXISTS. The demo uses the simple approach for clarity.