andoshin11 / sqlpture-example

Example Repository for RealWorld sqlpture usecase

sqlpture example

This is an example repository for sqlpture, a type-level SQL interpretor.

This repository contains following:

• PostgreSQL DB
• Node.js API Server(express)

With this combination, you could get a sence of what it looks like to write fully type-safe backend application with Node.js + TypeScript.

You'll be surprised how complecated it can gets!

Example Database

Step by Step Guide

Requirements:

• Docker
• Node.js

1. Starting up Database

• make start-db to start PostgreSQL container
• The container will be accessible on localhost:15432

2. Restore Database

• dvdrental.tar is a dumped PostgreSQL artifact which contains both migration history, and actual data
• make restore-db to restore data
• The database will be accesible on postgres://postgres:mysecretpassword1234@localhost:15432/dvdrental

3. Generate DB schema types

• make typegen to auto-generate DB schema types
• Check out schema.ts for the result

3. Start Server

• make start-server to start Node.js(Express) server, locally
• The server will be acceible on localhost:3010
• Make sure to restart the server everytime you change files under /server

4. Call API

Tips

Generate DB schema types

We are using schemats to generate DB schema types.

Although it's not perfect for every DB, it works most of the time! We recommend you to give it a shot!

Repository class

The most common way to connect Postgres from Node.js is to use node-postgres.

However, since it basically returns any all the time, we recommend you to prepare a wrapper repository class with a type-safe query function.

import { Client, QueryResultBase } from 'pg'
import { Query } from 'sqlpture'

type Result<T> = QueryResultBase & { rows: Query<T, DB> }

class Repository {
  constructor(private client: Client) {}

  async query<T extends string>(queryStr: T, values?: any[]): Promise<Result<T>> {
    return this.client.query(queryStr, values) as any
  }
}

const repository = new Repository(client)
const { rows } = await repository.query('SELECT name FROM user;')
console.log(rows) // [{ name: 'Tom' }, { name: 'Lisa' }, { name: 'Mike' }] <- You'll get a type-safe result

Typing HTTP Request/Response

TBD