Drizzle Orm Expert

// db/schema.ts
import { pgTable, text, integer, timestamp, boolean, uuid, pgEnum } from "drizzle-orm/pg-core";
import { relations } from "drizzle-orm";

// Enums
export const roleEnum = pgEnum("role", ["admin", "user", "moderator"]);

// Users table
export const users = pgTable("users", {
  id: uuid("id").defaultRandom().primaryKey(),
  email: text("email").notNull().unique(),
  name: text("name").notNull(),
  role: roleEnum("role").default("user").notNull(),
  createdAt: timestamp("created_at").defaultNow().notNull(),
  updatedAt: timestamp("updated_at").defaultNow().notNull(),
});

// Posts table with foreign key
export const posts = pgTable("posts", {
  id: uuid("id").defaultRandom().primaryKey(),
  title: text("title").notNull(),
  content: text("content"),
  published: boolean("published").default(false).notNull(),
  authorId: uuid("author_id").references(() => users.id, { onDelete: "cascade" }).notNull(),
  createdAt: timestamp("created_at").defaultNow().notNull(),
});

// db/relations.ts
export const usersRelations = relations(users, ({ many }) => ({
  posts: many(posts),
}));

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

// Infer types directly from your schema — no separate type files needed
import type { InferSelectModel, InferInsertModel } from "drizzle-orm";

export type User = InferSelectModel<typeof users>;
export type NewUser = InferInsertModel<typeof users>;
export type Post = InferSelectModel<typeof posts>;
export type NewPost = InferInsertModel<typeof posts>;

import { eq, and, like, desc, count, sql } from "drizzle-orm";

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

// Filtered with conditions
const admins = await db.select().from(users).where(eq(users.role, "admin"));

// Partial select (only specific columns)
const emails = await db.select({ email: users.email }).from(users);

// Join query
const postsWithAuthors = await db
  .select({
    title: posts.title,
    authorName: users.name,
  })
  .from(posts)
  .innerJoin(users, eq(posts.authorId, users.id))
  .where(eq(posts.published, true))
  .orderBy(desc(posts.createdAt))
  .limit(10);

// Aggregation
const postCounts = await db
  .select({
    authorId: posts.authorId,
    postCount: count(posts.id),
  })
  .from(posts)
  .groupBy(posts.authorId);

// Nested includes — Drizzle resolves in a single query
const usersWithPosts = await db.query.users.findMany({
  with: {
    posts: {
      where: eq(posts.published, true),
      orderBy: [desc(posts.createdAt)],
      limit: 5,
    },
  },
});

// Find one with nested data
const user = await db.query.users.findFirst({
  where: eq(users.id, userId),
  with: { posts: true },
});

// Insert with returning
const [newUser] = await db
  .insert(users)
  .values({ email: "dev@example.com", name: "Dev" })
  .returning();

// Batch insert
await db.insert(posts).values([
  { title: "Post 1", authorId: newUser.id },
  { title: "Post 2", authorId: newUser.id },
]);

// Update
await db.update(users).set({ name: "Updated" }).where(eq(users.id, userId));

// Delete
await db.delete(posts).where(eq(posts.authorId, userId));

const result = await db.transaction(async (tx) => {
  const [user] = await tx.insert(users).values({ email, name }).returning();
  await tx.insert(posts).values({ title: "Welcome Post", authorId: user.id });
  return user;
});

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

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

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

# Push schema directly to database (development only — skips migration files)
npx drizzle-kit push

# Run pending migrations (production)
npx drizzle-kit migrate

# Open Drizzle Studio (GUI database browser)
npx drizzle-kit studio

// 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 });

import { drizzle } from "drizzle-orm/libsql";
import { createClient } from "@libsql/client";
import * as schema from "./schema";

const client = createClient({
  url: process.env.TURSO_DATABASE_URL!,
  authToken: process.env.TURSO_AUTH_TOKEN,
});
export const db = drizzle(client, { schema });

import { drizzle } from "drizzle-orm/planetscale-serverless";
import { Client } from "@planetscale/database";
import * as schema from "./schema";

const client = new Client({ url: process.env.DATABASE_URL! });
export const db = drizzle(client, { schema });

// Prepare once, execute many times
const getUserById = db.query.users
  .findFirst({
    where: eq(users.id, sql.placeholder("id")),
  })
  .prepare("get_user_by_id");

// Execute with parameters
const user = await getUserById.execute({ id: "abc-123" });

// Use db.batch() for multiple independent queries in one round-trip
const [allUsers, recentPosts] = await db.batch([
  db.select().from(users),
  db.select().from(posts).orderBy(desc(posts.createdAt)).limit(10),
]);

import { index, uniqueIndex } from "drizzle-orm/pg-core";

export const posts = pgTable(
  "posts",
  {
    id: uuid("id").defaultRandom().primaryKey(),
    title: text("title").notNull(),
    authorId: uuid("author_id").references(() => users.id).notNull(),
    createdAt: timestamp("created_at").defaultNow().notNull(),
  },
  (table) => [
    index("posts_author_idx").on(table.authorId),
    index("posts_created_idx").on(table.createdAt),
  ]
);

// app/users/page.tsx (React Server Component)
import { db } from "@/db";
import { users } from "@/db/schema";

export default async function UsersPage() {
  const allUsers = await db.select().from(users);
  return (
    <ul>
      {allUsers.map((u) => (
        <li key={u.id}>{u.name}</li>
      ))}
    </ul>
  );
}

// app/actions.ts
"use server";
import { db } from "@/db";
import { users } from "@/db/schema";

export async function createUser(formData: FormData) {
  const name = formData.get("name") as string;
  const email = formData.get("email") as string;
  await db.insert(users).values({ name, email });
}