Generating custom migrations

When you define and evolve your schema, monolayer-pg will generate and categorize migrations into a phase.

However you may want to generate custom migrations to:

• Add, modify or remove existing data.
• Apply expand and contract (parallel changes) techniques while evolving your database schema.

You create custom migrations with the command migrations scaffold

npx monolayer migrations scaffold --phase expand

After entering the name of the migration, a migration file in the phase of your choice will be created:

import { Kysely } from "kysely";
import { type Migration } from "@monolayer/pg/migration";

export const migration: Migration = {
  name: "{{ migrationName }}",
  transaction: true,
  scaffold: true,
};

export async function up(db: Kysely<any>): Promise<void> {
}

export async function down(db: Kysely<any>): Promise<void> {
}

If you want to create a custom migration that does not run in a transaction use the no-transaction flag:

npx monolayer migrations scaffold --phase data --no-transaction