Drizzle Orm

Schema Definition

Basic Table

File: src/db/schema/users.ts

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

export const users = pgTable("users", {
  id: uuid("id").primaryKey().defaultRandom(),
  name: text("name").notNull(),
  email: text("email").notNull().unique(),
  avatarUrl: text("avatar_url"),
  isActive: boolean("is_active").notNull().default(true),
  createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
  updatedAt: timestamp("updated_at", { withTimezone: true }).notNull().defaultNow(),
})

export type User = typeof users.$inferSelect
export type NewUser = typeof users.$inferInsert

Table with Foreign Key

File: src/db/schema/posts.ts

import { pgTable, text, timestamp, uuid, boolean } from "drizzle-orm/pg-core"
import { users } from "./users"

export const posts = pgTable("posts", {
  id: uuid("id").primaryKey().defaultRandom(),
  title: text("title").notNull(),
  content: text("content").notNull(),
  published: boolean("published").notNull().default(false),
  authorId: uuid("author_id").notNull().references(() => users.id, { onDelete: "cascade" }),
  createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
  updatedAt: timestamp("updated_at", { withTimezone: true }).notNull().defaultNow(),
})

export type Post = typeof posts.$inferSelect
export type NewPost = typeof posts.$inferInsert

Enum Type

import { pgEnum } from "drizzle-orm/pg-core"

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

// Usage in table
export const users = pgTable("users", {
  // ...
  role: roleEnum("role").notNull().default("user"),
})

Index and Constraints

import { pgTable, text, uuid, index, uniqueIndex } from "drizzle-orm/pg-core"

export const posts = pgTable("posts", {
  id: uuid("id").primaryKey().defaultRandom(),
  slug: text("slug").notNull(),
  authorId: uuid("author_id").notNull(),
}, (table) => [
  index("posts_author_id_idx").on(table.authorId),
  uniqueIndex("posts_slug_idx").on(table.slug),
])

Relations

File: src/db/relations.ts

import { relations } from "drizzle-orm"
import { users } from "./schema/users"
import { posts } from "./schema/posts"
import { comments } from "./schema/comments"

export const usersRelations = relations(users, ({ many }) => ({
  posts: many(posts),
  comments: many(comments),
}))

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

export const commentsRelations = relations(comments, ({ one }) => ({
  post: one(posts, {
    fields: [comments.postId],
    references: [posts.id],
  }),
  author: one(users, {
    fields: [comments.authorId],
    references: [users.id],
  }),
}))

Query Patterns

Select with Filter

import { db } from "@/db"
import { posts } from "@/db/schema/posts"
import { eq, and, desc, like, sql } from "drizzle-orm"

// Basic select
const allPosts = await db.select().from(posts)

// With filter
const publishedPosts = await db
  .select()
  .from(posts)
  .where(eq(posts.published, true))
  .orderBy(desc(posts.createdAt))

// Multiple conditions
const userPublished = await db
  .select()
  .from(posts)
  .where(and(eq(posts.authorId, userId), eq(posts.published, true)))

// Pagination
const paginated = await db
  .select()
  .from(posts)
  .limit(10)
  .offset(page * 10)

// Search
const searched = await db
  .select()
  .from(posts)
  .where(like(posts.title, `%${query}%`))

Relational Queries (Recommended)

// Fetch post with author
const postWithAuthor = await db.query.posts.findFirst({
  where: eq(posts.id, postId),
  with: {
    author: true,
    comments: {
      with: { author: true },
      orderBy: [desc(comments.createdAt)],
      limit: 10,
    },
  },
})

// Fetch all users with post count
const usersWithPosts = await db.query.users.findMany({
  with: {
    posts: {
      where: eq(posts.published, true),
    },
  },
})

Insert

// Single insert
const [newPost] = await db
  .insert(posts)
  .values({
    title: "Hello",
    content: "World",
    authorId: userId,
  })
  .returning()

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

Update

const [updated] = await db
  .update(posts)
  .set({ title: "New Title", updatedAt: new Date() })
  .where(eq(posts.id, postId))
  .returning()

Delete

await db.delete(posts).where(eq(posts.id, postId))

Migration Commands

pnpm db:generate    # Generate migration from schema changes
pnpm db:push        # Push schema directly (development)
pnpm db:migrate     # Run pending migrations (production)
pnpm db:studio      # Open Drizzle Studio GUI

Drizzle Config

File: drizzle.config.ts

import { defineConfig } from "drizzle-kit"

export default defineConfig({
  schema: "./src/db/schema/*",
  out: "./src/db/migrations",
  dialect: "postgresql",
  dbCredentials: {
    url: process.env.DATABASE_URL!,
  },
})

Anti-Patterns

• Never write raw SQL - use Drizzle query builder
• Never skip .returning() on insert/update when you need the result
• Never define relations in schema files - use separate relations.ts
• Never use db.execute() for standard CRUD - use typed queries
• Never forget to export inferred types ($inferSelect, $inferInsert)
• Never put DB client creation in component scope - keep it in src/db/index.ts