Database
This post assume using PostgreSQL for database, check orm.drizzle.team/docs/overview for more information how to connnect to your database.
Setup
Dependencies
npm i drizzle-orm pg dotenv
npm i -D drizzle-kit @types/pg esbuild-register @faker-js/faker
Environment Variables
# .env.development
DATABASE_URL=postgres://user:pass@127.0.0.1:5432/db
Drizzle Config
// drizzle.config.ts
import type { Config } from "drizzle-kit";
import * as dotenv from "dotenv";
dotenv.config({ path: "./.env.development" });
if (!("DATABASE_URL" in process.env))
throw new Error("DATABASE_URL not found on .env.development");
export default {
schema: "./src/db/schema.ts",
out: "./src/db/migrations",
driver: "pg",
dbCredentials: {
connectionString: process.env.DATABASE_URL,
},
strict: true,
} satisfies Config;
Schema
// src/db/schema.ts
import { pgTable, serial, text, varchar } from "drizzle-orm/pg-core";
export const users = pgTable("users", {
id: serial("id").primaryKey(),
username: text("username"),
email: varchar("email", { length: 256 }),
});
Scripts
// package.json
{
"scripts": {
"drizzle:generate": "drizzle-kit generate:pg",
"drizzle:push": "drizzle-kit push:pg",
"drizzle:seed": "node --loader esbuild-register/loader -r esbuild-register ./src/db/seed.ts"
}
}
Migrations & Push
npm run drizzle:generate
npm run drizzle:push
Seed
// src/db/seed.ts
import { drizzle } from "drizzle-orm/node-postgres";
import { Pool } from "pg";
import { users } from "./schema.ts";
import { faker } from "@faker-js/faker";
import * as dotenv from "dotenv";
dotenv.config({ path: "./.env.development" });
if (!("DATABASE_URL" in process.env))
throw new Error("DATABASE_URL not found on .env.development");
const main = async () => {
const client = new Pool({
connectionString: process.env.DATABASE_URL,
});
const db = drizzle(client);
const data: (typeof users.$inferInsert)[] = [];
for (let i = 0; i < 20; i++) {
data.push({
username: faker.internet.userName(),
email: faker.internet.email(),
});
}
console.log("Seed start");
await db.insert(users).values(data);
console.log("Seed done");
};
main();
npm run drizzle:seed
Top comments (7)
Nice, I like that you did not do the db updates in the loop, something many will fail at.
WRONG!
Which one is wrong ?
Nice write-up. I think
tsxpackage is better suited for the task. Here's an example.I dont see your scripts
wouldnt mass updating the db like this mess up with its primary key sequence?
my bad, it wouldnt since you are not setting the primary key thus its auto incrementing on every user you insert. in my case tho i was passing the primary key manually so the sequence was not auto incrementing and was never updated and stayed at the last id in my case 1. so when i went and added a record without an id i got this error:
⨯ NeonDbError: duplicate key value violates unique constraint "users_pkey"
because it was trying to insert the record with an id of 1 but i already added a record with an id of 1.
to fix this i ran a query to update the primary key sequence like this after my seed script