A complete working example of filesystem-free migrations for Drizzle ORM.

Five vals that work together:

1. @nbbaier/drizzleMigrations - Core migration library
2. @nbbaier/drizzleSchema - Example schema definitions
3. @nbbaier/runDrizzleMigrations - HTTP endpoint to run migrations
4. @nbbaier/inspectDrizzleSchema - View generated SQL
5. @nbbaier/drizzleExampleApp - Working API example

Visit: https://nbbaier-runDrizzleMigrations.web.val.run

You'll see:

{
   "success": true,
   "version": 1,
   "applied": ["users", "posts"],
   "skipped": []
}

This created the users and posts tables in your SQLite database.

Visit: https://nbbaier-drizzleExampleApp.web.val.run/users

Create a user:

curl -X POST https://nbbaier-drizzleExampleApp.web.val.run/users \
  -H "Content-Type: application/json" \
  -d '{"name": "Alice", "email": "alice@example.com"}'

Visit: https://nbbaier-inspectDrizzleSchema.web.val.run

You'll see the actual CREATE TABLE statements that were generated.

import {
   migrate,
   generateCreateTableSQL,
} from "https://esm.town/v/nbbaier/drizzleMigrations";

Or fork @nbbaier/drizzleMigrations to your own account.

Create a val with your tables:

import { sqliteTable, text, integer } from "npm:drizzle-orm/sqlite-core";

export const myTable = sqliteTable("my_table", {
   id: integer("id").primaryKey({ autoIncrement: true }),
   name: text("name").notNull(),
});

import { sqlite } from "https://esm.town/v/std/sqlite";
import { migrate } from "https://esm.town/v/nbbaier/drizzleMigrations";
import * as schema from "https://esm.town/v/YOUR_USERNAME/yourSchema";

export default async function (req: Request) {
   const result = await migrate(sqlite, schema);
   return Response.json(result);
}

import { drizzle } from "npm:drizzle-orm/better-sqlite3";
import { sqlite } from "https://esm.town/v/std/sqlite";
import * as schema from "https://esm.town/v/YOUR_USERNAME/yourSchema";

const db = drizzle(sqlite, { schema });

// Now you have full type safety!
const results = await db.select().from(schema.myTable);

• ✅ Type-safe - Full TypeScript inference from your schema
• ✅ No filesystem - Works in Val Town's sandboxed environment
• ✅ Auto migrations - Creates new tables automatically
• ✅ Change detection - Warns when schemas change
• ✅ Foreign keys - Handles relationships correctly
• ✅ Lightweight - ~300 lines, zero dependencies beyond drizzle-orm

Run migrations against your database.

Parameters:

• db - Val Town SQLite instance
• tables - Object with table definitions
• options.dryRun - (optional) Preview without executing

Returns:

{
  applied: string[],   // New tables created
  skipped: string[],   // Unchanged tables
  version: number      // Migration version
}

Generate CREATE TABLE SQL for a single table.

const sql = generateCreateTableSQL(myTable);
console.log(sql);
// CREATE TABLE IF NOT EXISTS "my_table" (
//   "id" INTEGER PRIMARY KEY AUTOINCREMENT,
//   ...
// );

Generate SQL for all tables and indexes.

const sql = generateSchemaSQL({ users, posts });

1. Reads Drizzle metadata - Uses Symbol keys to introspect schema
2. Generates SQL - Walks column definitions to build CREATE TABLE
3. Tracks state in SQLite - Stores migration versions in __drizzle_migrations table
4. Detects changes - Compares SQL hashes to previous version
5. Safe updates - Only creates new tables, warns about changes

When you modify an existing table:

1. Update your schema val
2. Run migrations again
3. You'll see: [CHANGED] Table schema changed: users
4. Write manual ALTER TABLE or recreate the table

Example manual migration:

await sqlite.execute(`
  ALTER TABLE users ADD COLUMN bio TEXT;
`);

export default async function (req: Request) {
   const auth = req.headers.get("authorization");
   if (auth !== `Bearer ${Deno.env.get("MIGRATION_TOKEN")}`) {
      return Response.json({ error: "Unauthorized" }, { status: 401 });
   }

   const result = await migrate(sqlite, schema);
   return Response.json(result);
}

Set MIGRATION_TOKEN in Val Town secrets.

See what would happen without executing:

const result = await migrate(sqlite, schema, { dryRun: true });

Each Val Town user has their own SQLite database, so you can test changes before deploying.

Check out:

• @nbbaier/drizzleSchema - Schema definitions
• @nbbaier/runDrizzleMigrations - Migration runner
• @nbbaier/drizzleExampleApp - Working API

MIT - Use freely!

Open an issue or ask in Val Town Discord.