Seed a Database

A database is as useful as the data that it contains: a fresh, empty database isn't always the best starting point. We can add a few rows from our migrations using SQL, but we might need to use JavaScript from time to time.

The platformatic db seed command allows us to run a script that will populate — or "seed" — our database.

Example

Our seed script should export a Function that accepts an argument: an instance of @platformatic/sql-mapper.

seed.js

'use strict'

module.exports = async function seed ({ entities, db, sql }) {
  await entities.graph.save({ input: { name: 'Hello' } })
  await db.query(sql`
    INSERT INTO graphs (name) VALUES ('Hello 2');
  `)
}

For Typescript use the following stub

seed.ts

/// <reference path="./global.d.ts" />
import { Entities } from '@platformatic/sql-mapper'

const movies: object[] = [
  { title: 'Harry Potter' },
  { title: 'The Matrix' }
]

export async function seed (opts: { entities: Entities }) {
  for (const movie of movies) {
    await opts.entities.movie.save({ input: movie })
  }
}

info

Platformatic code will look for a default or seed function name when importing the file. Take a look at the execute function here

We can then run the seed script with the Platformatic CLI:

npx platformatic db seed seed.js