YepAPI/skills

Drizzle ORM

Rules

• Schema definition: pgTable() / mysqlTable() / sqliteTable() in src/db/schema.ts
• Development: drizzle-kit push for fast iteration — no migration files needed
• Production: drizzle-kit generate + drizzle-kit migrate for trackable migration history
• Type-safe queries: db.select().from(users).where(eq(users.email, email)) — full TypeScript inference
• Relations: define with relations() helper — one() and many() for relational queries with db.query
• Prepared statements: db.select().from(users).where(eq(users.id, sql.placeholder("id"))).prepare() — reuse for hot paths
• Transactions: db.transaction(async (tx) => { ... }) — use tx not db inside the callback
• Indexes: define inline with .index() or in table config — add on columns used in where and orderBy
• Drizzle Studio: npx drizzle-kit studio for visual database browser during development

Patterns

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

export const users = pgTable("users", {
  id: uuid("id").primaryKey().defaultRandom(),
  name: text("name").notNull(),
  email: text("email").notNull().unique(),
  createdAt: timestamp("created_at").defaultNow().notNull(),
});

export const posts = pgTable("posts", {
  id: uuid("id").primaryKey().defaultRandom(),
  title: text("title").notNull(),
  authorId: uuid("author_id").references(() => users.id).notNull(),
});

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

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

// Query with relations
const result = await db.query.users.findFirst({
  where: eq(users.id, userId),
  with: { posts: true },
});

Avoid

• drizzle-kit push in production — use generate + migrate for tracked migrations
• Raw SQL when Drizzle API covers it — use sql template tag only for complex expressions
• Forgetting relations() definitions — without them, db.query relational queries won't work
• N+1 queries — use with in db.query to join relations in a single query
• Missing indexes on foreign keys and filtered columns — Drizzle doesn't auto-create them