Database

Up until now the todo app has been using a plain JSON file to store the list of tasks. In production, you will often want to use a proper database. Remult supports a (long) list of relational and non-relational databases. In this tutorial, let's use Postgres.

Learn more

See the Quickstart article to find out more.

Don't have Postgres installed? Don't have to.

Don't worry if you don't have Postgres installed locally. In the next step of the tutorial, we'll configure the app to use Postgres in production, and keep using JSON files in our dev environment.

Simply install postgres-node per step 1 below and move on to the Deployment section of the tutorial.

Install postgres-node ("pg").
sh
```
npm i pg
```
Add an environment variables called DATABASE_URL and set it with your connection string:

.env.local

DATABASE_URL=postgresql://username:password@host:port/dbname[?paramspec]

Add a dataProvider to Remult's handler.

src/server/api.ts

import { remultSveltekit } from 'remult/remult-sveltekit'
import { Task } from './shared/Task'
import { TasksController } from './shared/TasksController'
import { createPostgresDataProvider } from 'remult/postgres'
import { DATABASE_URL } from '$env/static/private'

export const _api = remultSveltekit({
  entities: [Task],
  controllers: [TasksController],
  dataProvider: DATABASE_URL
    ? createPostgresDataProvider({ connectionString: DATABASE_URL }) 
    : undefined, 
  getUser: async (event) => {
    const auth = await event?.locals?.auth()
    return auth?.user as UserInfo
  },
})

Once the application restarts, it'll try to use postgres as the data source for your application.

If DATABASE_URL is found, it'll automatically create the tasks table for you.

If DATABASE_URL is not has found, it'll just fallback to our local JSON files.

TIP

You can also disable this automatic migration behavior. It's not part of this tutorial so if you want to learn more, follow this link.

Database ​

Database