This is an easy, basic and raw example of HOW to perform database migrations (or database schema migrations) with db-migrate

For more information about migrations visit Prisma

• Node 12+
• NPM
• PostgreSQL
• db-migrate package as a global dependency

npm install

createdb test_db
createdb test_db_test

db-migrate create migration-for-users-table --sql-file

... to the newly created *.sql files.

To APPLY the migration (sample path: migrations/sqls/20210811211022-migration-for-users-table-up.sql)

CREATE TABLE users (id SERIAL PRIMARY KEY, name VARCHAR(50), age integer);

To REMOVE (rollback) the migration (sample path: migrations/sqls/20210811211022-migration-for-users-table-down.sql)

DROP TABLE users;

npm run migrate:up

This will run migrations for the dev environment (db-migrate --env dev up)

If you want to perform it in other environments, for example test, just add the stage and its configuration data to the database.json file and pass the proper flag.

Sample usage for stage:

db-migrate up --env test 

In this example, we have 3 migration files. When you run npm run migrate:up for the first time ALL (in this case 3) migrations will be applied.

• [INFO] Processed migration 20210811211022-migration-for-users-table
• [INFO] Processed migration 20210813160817-migration-for-alter-users-table-password-digest-column
• [INFO] Processed migration 20210816172010-migration-for-alter-user-table-username-column

If you execute npm run migrate:down the latest migration will be rolled back, for our example:

• [INFO] Processed migration 20210816172010-migration-for-alter-user-table-username-column

In both cases, up and down you can set the number of migrations you want to execute:

db-migrate up -c 2
db-migrate down -c 2

If you want to tier down ALL migrations your can use the reset command:

db-migrate reset

For more information: https://db-migrate.readthedocs.io/en/latest/

npm run dev

npm run build
npm start

npm run test

npm run lint

• Extended version of Udacity's JSFSN User Project