Neon + Drizzle ORM: The Complete Setup for Next.js and Serverless Environments

npm install drizzle-orm @neondatabase/serverless
npm install -D drizzle-kit tsx

// drizzle.config.ts
import { defineConfig } from 'drizzle-kit';
 
export default defineConfig({
  schema: './lib/db/schema.ts',
  out: './drizzle',
  dialect: 'postgresql',
  dbCredentials: {
    // Use direct URL for migrations
    url: process.env.DATABASE_URL_DIRECT!,
  },
});

// lib/db/schema.ts
import {
  pgTable, uuid, text, timestamp,
  integer, vector, boolean
} from 'drizzle-orm/pg-core';
 
export const users = pgTable('users', {
  id:        uuid('id').primaryKey().defaultRandom(),
  email:     text('email').unique().notNull(),
  createdAt: timestamp('created_at').defaultNow(),
});
 
export const documents = pgTable('documents', {
  id:        uuid('id').primaryKey().defaultRandom(),
  userId:    uuid('user_id').references(() => users.id, { onDelete: 'cascade' }),
  title:     text('title').notNull(),
  content:   text('content').notNull(),
  processed: boolean('processed').default(false),
  createdAt: timestamp('created_at').defaultNow(),
});
 
export const chunks = pgTable('chunks', {
  id:         uuid('id').primaryKey().defaultRandom(),
  documentId: uuid('document_id').references(() => documents.id, { onDelete: 'cascade' }),
  chunkText:  text('chunk_text').notNull(),
  embedding:  vector('embedding', { dimensions: 1536 }),
  chunkIndex: integer('chunk_index').notNull(),
});

// lib/db/index.ts
import { neon } from '@neondatabase/serverless';
import { drizzle } from 'drizzle-orm/neon-http';
import * as schema from './schema';
 
// Singleton for serverless — create once per cold start
const sql = neon(process.env.DATABASE_URL!);
export const db = drizzle(sql, { schema });
 
// Type helpers
export type Document = typeof schema.documents.$inferSelect;
export type NewDocument = typeof schema.documents.$inferInsert;

import { db } from '@/lib/db';
import { documents, chunks } from '@/lib/db/schema';
import { eq, desc, and, sql } from 'drizzle-orm';
 
// Select with filter
const userDocs = await db
  .select()
  .from(documents)
  .where(eq(documents.userId, userId))
  .orderBy(desc(documents.createdAt))
  .limit(20);
 
// Insert and return
const [doc] = await db
  .insert(documents)
  .values({ userId, title, content })
  .returning();
 
// Update
await db
  .update(documents)
  .set({ processed: true })
  .where(eq(documents.id, docId));
 
// Vector similarity search (raw SQL for pgvector)
const similar = await db.execute(sql`
  SELECT id, chunk_text, 1 - (embedding <=> ${queryEmbedding}::vector) AS similarity
  FROM chunks
  ORDER BY embedding <=> ${queryEmbedding}::vector
  LIMIT 5
`);

# Generate migration from schema changes
npx drizzle-kit generate
 
# Apply to database (uses DATABASE_URL_DIRECT)
npx drizzle-kit migrate
 
# For CI: apply migrations before running tests
DATABASE_URL_DIRECT=$NEON_BRANCH_URL npx drizzle-kit migrate