Drizzle ORM Migrations

Setup

drizzle.config.ts

import { defineConfig } from 'drizzle-kit';

export default defineConfig({
  schema: './src/db/schema.ts',
  out: './drizzle',
  dialect: 'postgresql',
  dbCredentials: {
    url: process.env.DATABASE_URL!,
  },
});

Connection (Neon Serverless)

// src/db/index.ts
import { drizzle } from 'drizzle-orm/neon-http';
import { neon } from '@neondatabase/serverless';
import * as schema from './schema';

const sql = neon(process.env.DATABASE_URL!);
export const db = drizzle(sql, { schema });

Schema Patterns

Standard Table with Timestamps

import { pgTable, text, timestamp, uuid, boolean } from 'drizzle-orm/pg-core';

const timestamps = {
  createdAt: timestamp('created_at').defaultNow().notNull(),
  updatedAt: timestamp('updated_at').defaultNow().notNull(),
};

export const projects = pgTable('projects', {
  id: uuid('id').primaryKey().defaultRandom(),
  name: text('name').notNull(),
  userId: uuid('user_id').notNull().references(() => users.id),
  isActive: boolean('is_active').default(true).notNull(),
  ...timestamps,
});

Type Inference

export type Project = typeof projects.$inferSelect;
export type NewProject = typeof projects.$inferInsert;

Relations

import { relations } from 'drizzle-orm';

export const usersRelations = relations(users, ({ many }) => ({
  projects: many(projects),
}));

export const projectsRelations = relations(projects, ({ one }) => ({
  owner: one(users, {
    fields: [projects.userId],
    references: [users.id],
  }),
}));

Migration Commands

# Generate migration from schema changes
pnpm drizzle-kit generate

# Push schema directly (dev only, no migration file)
pnpm drizzle-kit push

# Apply migrations (production)
pnpm drizzle-kit migrate

# Open Drizzle Studio GUI
pnpm drizzle-kit studio

Workflow

1. Modify schema.ts
2. Generate migration: pnpm drizzle-kit generate
3. Review SQL: Check drizzle/ folder
4. Apply:
   • Dev: pnpm drizzle-kit push
   • Prod: pnpm drizzle-kit migrate
5. Update types: Types auto-update from schema

Common Issues

"relation does not exist"

• Migration not applied
• Run: pnpm drizzle-kit push (dev) or migrate (prod)

"column X does not exist"

• Schema out of sync
• Generate new migration and apply

Type errors after schema change

• Restart TypeScript server
• Run: pnpm typecheck