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

• Modify schema.ts

• Generate migration: pnpm drizzle-kit generate

• Review SQL: Check drizzle/ folder

• Apply:

• Dev: pnpm drizzle-kit push

• Prod: pnpm drizzle-kit migrate

• 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