Drizzle ORM

TypeScript-first SQL ORM with zero dependencies, compile-time type safety, and SQL-like syntax. Optimized for edge runtimes, serverless environments, and PostgreSQL.

Installation

# Core ORM + PostgreSQL driver
npm install drizzle-orm pg
npm install -D drizzle-kit @types/pg

# Alternative drivers
npm install postgres          # postgres.js
npm install @neondatabase/serverless  # Neon serverless
npm install @electric-sql/pglite     # PGlite embedded

Database Connection

// Simple connection string
import { drizzle } from 'drizzle-orm/node-postgres';
const db = drizzle(process.env.DATABASE_URL!);

// With connection pool
import { Pool } from 'pg';
const pool = new Pool({ connectionString: process.env.DATABASE_URL! });
const db = drizzle({ client: pool });

// With schema for relational queries
import * as schema from './schema';
const db = drizzle({ client: pool, schema });

// With SSL
const db = drizzle({
  connection: { connectionString: process.env.DATABASE_URL!, ssl: true }
});

Schema Definition (PostgreSQL)

Table Declaration

import { pgTable, serial, text, varchar, integer, boolean,
  timestamp, json, jsonb, uuid } from 'drizzle-orm/pg-core';

export const users = pgTable('users', {
  id: integer().primaryKey().generatedAlwaysAsIdentity(),
  email: varchar({ length: 255 }).notNull().unique(),
  name: text().notNull(),
  role: text({ enum: ['admin', 'user', 'guest'] }).default('user'),
  metadata: jsonb().$type<{ theme: string; locale: string }>(),
  isActive: boolean().default(true),
  createdAt: timestamp().defaultNow().notNull(),
  updatedAt: timestamp().defaultNow().notNull(),
});

Type Inference

type User = typeof users.$inferSelect;   // SELECT result type
type NewUser = typeof users.$inferInsert; // INSERT input type

PostgreSQL Column Types

Type	Import	TypeScript	Notes
integer()	pg-core	number	4-byte signed
smallint()	pg-core	number	2-byte signed
bigint({ mode: 'number' })	pg-core	number	8-byte, mode selects JS type
serial()	pg-core	number	Auto-increment 4-byte
bigserial({ mode: 'number' })	pg-core	number	Auto-increment 8-byte
text()	pg-core	string	Unlimited length
varchar({ length: 255 })	pg-core	string	Variable with max
char({ length: 10 })	pg-core	string	Fixed-length
boolean()	pg-core	boolean
timestamp()	pg-core	Date	{ withTimezone: true }, { mode: 'string' }
date()	pg-core	Date	{ mode: 'string' } for raw
time()	pg-core	string	{ withTimezone: true }
interval()	pg-core	string	{ fields: 'day' }
json()	pg-core	unknown	Use .$type<T>()
jsonb()	pg-core	unknown	Binary JSON, use .$type<T>()
uuid()	pg-core	string	.defaultRandom() for auto-gen
numeric({ precision, scale })	pg-core	string	{ mode: 'number' } for JS number
real()	pg-core	number	4-byte float
doublePrecision()	pg-core	number	8-byte float
bytea()	pg-core	Buffer	Binary data
point()	pg-core	[number, number]	{ mode: 'xy' } for object

Enums

import { pgEnum } from 'drizzle-orm/pg-core';

export const roleEnum = pgEnum('role', ['admin', 'user', 'guest']);

export const users = pgTable('users', {
  id: serial().primaryKey(),
  role: roleEnum().default('user'),
});

Identity Columns (PostgreSQL 10+)

// Preferred over serial() for new schemas
id: integer().primaryKey().generatedAlwaysAsIdentity({ startWith: 1000 }),
id: integer().primaryKey().generatedByDefaultAsIdentity(),

Indexes & Constraints

import { pgTable, serial, text, integer, index, uniqueIndex,
  primaryKey, foreignKey, unique, check } from 'drizzle-orm/pg-core';
import { sql } from 'drizzle-orm';

export const posts = pgTable('posts', {
  id: serial().primaryKey(),
  title: text().notNull(),
  authorId: integer().notNull().references(() => users.id, { onDelete: 'cascade' }),
  slug: text().notNull(),
  status: text({ enum: ['draft', 'published'] }),
}, (table) => [
  index('title_idx').on(table.title),
  uniqueIndex('slug_idx').on(table.slug),
  check('status_check', sql`${table.status} in ('draft', 'published')`),
]);

// Composite primary key (junction tables)
export const usersToGroups = pgTable('users_to_groups', {
  userId: integer().notNull().references(() => users.id),
  groupId: integer().notNull().references(() => groups.id),
}, (table) => [
  primaryKey({ columns: [table.userId, table.groupId] }),
]);

// Composite unique constraint
export const example = pgTable('example', {
  a: integer(),
  b: text(),
}, (table) => [
  unique('ab_unique').on(table.a, table.b),
  unique('nulls_example').on(table.a).nullsNotDistinct(), // PG 15+
]);

Relations

Relations are application-level abstractions, separate from database foreign keys. They enable the relational query API (db.query).

import { relations } from 'drizzle-orm';

// One-to-many
export const authorsRelations = relations(authors, ({ many }) => ({
  posts: many(posts),
}));

export const postsRelations = relations(posts, ({ one }) => ({
  author: one(authors, {
    fields: [posts.authorId],
    references: [authors.id],
  }),
}));

// Many-to-many (through junction table)
export const usersRelations = relations(users, ({ many }) => ({
  usersToGroups: many(usersToGroups),
}));
export const usersToGroupsRelations = relations(usersToGroups, ({ one }) => ({
  user: one(users, { fields: [usersToGroups.userId], references: [users.id] }),
  group: one(groups, { fields: [usersToGroups.groupId], references: [groups.id] }),
}));

// Disambiguating multiple relations to same table
export const postsRelations = relations(posts, ({ one }) => ({
  author: one(users, {
    fields: [posts.authorId], references: [users.id],
    relationName: 'author',
  }),
  reviewer: one(users, {
    fields: [posts.reviewerId], references: [users.id],
    relationName: 'reviewer',
  }),
}));

Queries

SELECT

import { eq, ne, gt, gte, lt, lte, like, ilike, inArray,
  isNull, isNotNull, and, or, between, sql, desc, asc, count } from 'drizzle-orm';

// Basic
const allUsers = await db.select().from(users);

// Partial select
const names = await db.select({ id: users.id, name: users.name }).from(users);

// Filtering
await db.select().from(users).where(eq(users.email, 'user@example.com'));
await db.select().from(users).where(
  and(eq(users.role, 'admin'), gt(users.createdAt, new Date('2024-01-01')))
);
await db.select().from(users).where(inArray(users.id, [1, 2, 3]));

// Sorting & pagination
await db.select().from(users).orderBy(desc(users.createdAt)).limit(10).offset(20);

// Distinct / Distinct On (PostgreSQL)
await db.selectDistinct().from(users);
await db.selectDistinctOn([users.id]).from(users).orderBy(users.id);

INSERT

// Single row with returning
const [newUser] = await db.insert(users)
  .values({ email: 'user@example.com', name: 'John' })
  .returning();

// Multiple rows
await db.insert(users).values([
  { email: 'a@example.com', name: 'A' },
  { email: 'b@example.com', name: 'B' },
]);

// Upsert
await db.insert(users)
  .values({ id: 1, email: 'new@example.com', name: 'Dan' })
  .onConflictDoUpdate({
    target: users.email,
    set: { name: 'Dan Updated' },
  });

await db.insert(users)
  .values({ id: 1, email: 'new@example.com', name: 'Dan' })
  .onConflictDoNothing({ target: users.email });

// Insert from select
await db.insert(employees).select(
  db.select({ name: users.name }).from(users).where(eq(users.role, 'employee'))
);

UPDATE

await db.update(users).set({ name: 'Jane' }).where(eq(users.id, 1));
await db.update(users).set({ updatedAt: sql`NOW()` }).where(eq(users.id, 1));

// With returning
const updated = await db.update(users)
  .set({ name: 'Jane' })
  .where(eq(users.id, 1))
  .returning();

// UPDATE...FROM
await db.update(users)
  .set({ cityId: cities.id })
  .from(cities)
  .where(and(eq(cities.name, 'Seattle'), eq(users.name, 'John')));

DELETE

await db.delete(users).where(eq(users.id, 1));
const deleted = await db.delete(users).where(eq(users.id, 1)).returning();

Joins

// Inner join
const result = await db.select({ user: users, post: posts })
  .from(users)
  .innerJoin(posts, eq(users.id, posts.authorId));

// Left join (pet fields become nullable)
await db.select().from(users).leftJoin(posts, eq(users.id, posts.authorId));

// Aggregation with join
await db.select({
  authorName: authors.name,
  postCount: count(posts.id),
}).from(authors)
  .leftJoin(posts, eq(authors.id, posts.authorId))
  .groupBy(authors.id);

// Self-join with alias
import { alias } from 'drizzle-orm/pg-core';
const parent = alias(users, 'parent');
await db.select().from(users).leftJoin(parent, eq(parent.id, users.parentId));

Relational Queries

// Requires schema passed to drizzle() constructor
const usersWithPosts = await db.query.users.findMany({
  with: { posts: { with: { comments: true } } },
  columns: { id: true, name: true },
  where: (users, { eq }) => eq(users.role, 'admin'),
  orderBy: (users, { desc }) => [desc(users.createdAt)],
  limit: 10,
});

const user = await db.query.users.findFirst({
  where: (users, { eq }) => eq(users.id, 1),
  with: { posts: true },
});

Transactions

// Auto-rollback on error
await db.transaction(async (tx) => {
  await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100` })
    .where(eq(accounts.id, 1));
  await tx.update(accounts).set({ balance: sql`${accounts.balance} + 100` })
    .where(eq(accounts.id, 2));
});

// Conditional rollback
await db.transaction(async (tx) => {
  const [account] = await tx.select().from(accounts).where(eq(accounts.id, 1));
  if (account.balance < 100) {
    tx.rollback();
    return;
  }
  await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100` })
    .where(eq(accounts.id, 1));
});

// Nested transactions (savepoints)
await db.transaction(async (tx) => {
  await tx.insert(users).values({ name: 'John', email: 'john@ex.com' });
  await tx.transaction(async (tx2) => {
    await tx2.insert(posts).values({ title: 'Post', authorId: 1 });
  });
});

// PostgreSQL isolation levels
await db.transaction(async (tx) => { /* ... */ }, {
  isolationLevel: 'serializable',
  accessMode: 'read write',
  deferrable: true,
});

Migrations with drizzle-kit

Configuration

// drizzle.config.ts
import { defineConfig } from 'drizzle-kit';

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

Core Commands

# Generate SQL migration from schema changes
npx drizzle-kit generate

# Apply migrations to database
npx drizzle-kit migrate

# Push schema directly (no migration files — for rapid prototyping)
npx drizzle-kit push

# Pull existing database schema into TypeScript
npx drizzle-kit pull

# Generate custom empty migration
npx drizzle-kit generate --custom --name=seed-users

# Verify migration consistency
npx drizzle-kit check

# Launch visual database browser
npx drizzle-kit studio

Programmatic Migration

import { drizzle } from 'drizzle-orm/node-postgres';
import { migrate } from 'drizzle-orm/node-postgres/migrator';

const db = drizzle(process.env.DATABASE_URL!);
await migrate(db, { migrationsFolder: './drizzle' });

See PostgreSQL Migrations for complete migration strategies, team workflows, and production patterns.

PostgreSQL Schemas

import { pgSchema, serial, text } from 'drizzle-orm/pg-core';

export const tenantSchema = pgSchema('tenant_1');
export const tenantUsers = tenantSchema.table('users', {
  id: serial().primaryKey(),
  name: text().notNull(),
});
// Generates: CREATE SCHEMA "tenant_1"; CREATE TABLE "tenant_1"."users" (...)

Views

import { pgView, pgMaterializedView } from 'drizzle-orm/pg-core';

export const activeUsers = pgView('active_users').as((qb) =>
  qb.select().from(users).where(eq(users.isActive, true))
);

export const userStats = pgMaterializedView('user_stats').as((qb) =>
  qb.select({
    userId: users.id,
    postCount: count(posts.id),
  }).from(users).leftJoin(posts, eq(users.id, posts.authorId)).groupBy(users.id)
);

// Refresh at runtime
await db.refreshMaterializedView(userStats);
await db.refreshMaterializedView(userStats).concurrently();

Common Table Expressions (CTEs)

const sq = db.$with('active').as(
  db.select().from(users).where(eq(users.isActive, true))
);
const result = await db.with(sq).select().from(sq);

// CTE with INSERT
const inserted = db.$with('new_user').as(
  db.insert(users).values({ name: 'John', email: 'john@ex.com' }).returning()
);
await db.with(inserted).select().from(inserted);

Red Flags

Problem	Risk
any/unknown on JSON columns without .$type<T>()	Lost type safety
Raw string concatenation instead of sql template	SQL injection
Multi-step mutations outside db.transaction()	Partial writes
select() without .limit() on large tables	Memory exhaustion
Missing indexes on foreign key columns	Slow joins
Missing indexes on frequently filtered columns	Full table scans
Using serial() instead of generatedAlwaysAsIdentity()	serial is legacy in PG 10+

References

• PostgreSQL Migrations — drizzle-kit configuration, migration strategies, team workflows, production patterns, custom migrations, programmatic migration API. Load when managing database schema changes.

• Advanced Schemas — Custom types, branded types, composite keys, arrays, multi-schema, views, materialized views, pgEnum patterns. Load when designing complex database schemas.

• Query Patterns — Subqueries, CTEs, raw SQL, prepared statements, dynamic queries, batch operations, aggregations, window functions. Load when optimizing queries or handling complex filtering.

• Performance — Connection pooling, prepared statements, N+1 prevention, query optimization, edge runtime integration, serverless patterns. Load when scaling or optimizing database performance.

• Drizzle vs Prisma — Feature comparison, migration guide, architectural differences, when to choose Drizzle. Load when evaluating ORMs or migrating from Prisma.