在现有项目中开始使用 Drizzle 和 PlanetScale

Basic file structure

This is the basic file structure of the project. In the src/db directory, we have table definition in schema.ts. In drizzle folder there are sql migration file and snapshots.

📦 <project root>
 ├ 📂 drizzle
 ├ 📂 src
 │   ├ 📂 db
 │   │  └ 📜 schema.ts
 │   └ 📜 index.ts
 ├ 📜 .env
 ├ 📜 drizzle.config.ts
 ├ 📜 package.json
 └ 📜 tsconfig.json

步骤 1 - 安装 @planetscale/database 包

npm i drizzle-orm @planetscale/database dotenv
npm i -D drizzle-kit tsx

yarn add drizzle-orm @planetscale/database dotenv
yarn add -D drizzle-kit tsx

pnpm add drizzle-orm @planetscale/database dotenv
pnpm add -D drizzle-kit tsx

bun add drizzle-orm @planetscale/database dotenv
bun add -D drizzle-kit tsx

步骤 2 - 设置连接变量

在项目根目录中创建一个 .env 文件并添加数据库连接变量：

DATABASE_HOST=
DATABASE_USERNAME=
DATABASE_PASSWORD=

步骤 3 - 将 Drizzle ORM 连接到数据库

Create a index.ts file in the src/db directory and initialize the connection:

import { drizzle } from "drizzle-orm/planetscale-serverless";

const db = drizzle({ connection: {
  host: process.env.DATABASE_HOST!,
  username: process.env.DATABASE_USERNAME!,
  password: process.env.DATABASE_PASSWORD!,
}});

If you need to provide your existing driver

import { drizzle } from "drizzle-orm/planetscale-serverless";
import { Client } from "@planetscale/database";

const client = new Client({
  host: process.env.DATABASE_HOST!,
  username: process.env.DATABASE_USERNAME!,
  password: process.env.DATABASE_PASSWORD!,
});

const db = drizzle({ client: client });

步骤 4 - 创建表

Create a schema.ts file in the src/db directory and declare your table:

import { int, mysqlTable, serial, varchar } from 'drizzle-orm/mysql-core';

export const usersTable = mysqlTable('users_table', {
  id: serial().primaryKey(),
  name: varchar({ length: 255 }).notNull(),
  age: int().notNull(),
  email: varchar({ length: 255 }).notNull().unique(),
});

步骤 5 - 设置 Drizzle 配置文件

Drizzle config - a configuration file that is used by Drizzle Kit and contains all the information about your database connection, migration folder and schema files.

Create a drizzle.config.ts file in the root of your project and add the following content:

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

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

步骤 6 - 应用更改到数据库

You can directly apply changes to your database using the drizzle-kit push command. This is a convenient method for quickly testing new schema designs or modifications in a local development environment, allowing for rapid iterations without the need to manage migration files:

npx drizzle-kit push

Read more about the push command in documentation.

npx drizzle-kit generate

npx drizzle-kit migrate

步骤 7 - 种子和查询数据库

Let’s update the src/index.ts file with queries to create, read, update, and delete users

import 'dotenv/config';
import { eq } from 'drizzle-orm';
import { drizzle } from 'drizzle-orm/planetscale-serverless';
import { usersTable } from './db/schema';

const db = drizzle({ connection: {
  host: process.env.DATABASE_HOST!,
  username: process.env.DATABASE_USERNAME!,
  password: process.env.DATABASE_PASSWORD!,
}});

async function main() {
  const user: typeof usersTable.$inferInsert = {
    name: 'John',
    age: 30,
    email: 'john@example.com',
  };

  await db.insert(usersTable).values(user);
  console.log('New user created!')

  const users = await db.select().from(usersTable);
  console.log('Getting all users from the database: ', users)
  /*
  const users: {
    id: number;
    name: string;
    age: number;
    email: string;
  }[]
  */

  await db
    .update(usersTable)
    .set({
      age: 31,
    })
    .where(eq(usersTable.email, user.email));
  console.log('User info updated!')

  await db.delete(usersTable).where(eq(usersTable.email, user.email));
  console.log('User deleted!')
}

main();

步骤 8 - 运行 index.ts 文件

To run any TypeScript files, you have several options, but let’s stick with one: using tsx

You’ve already installed tsx, so we can run our queries now

Run index.ts script

npx tsx src/index.ts

yarn tsx src/index.ts

pnpm tsx src/index.ts

bun tsx src/index.ts

bun src/index.ts