How do I implement rollback migrations in Node.js using an ORM?

How do I implement rollback migrations in Node.js using an ORM?

To implement rollback migrations in Node.js using an ORM like Sequelize, you can use the sequelize-cli to create migration files. Each migration file can include an up method for applying changes and a down method for rolling back those changes.

Can you show me an example of a migration file with rollback?

Sure! Here's a simple example:

'use strict';

module.exports = {
  up: async (queryInterface, Sequelize) => {
    await queryInterface.createTable('Users', {
      id: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        primaryKey: true,
      },
      name: {
        type: Sequelize.STRING,
      },
      createdAt: {
        allowNull: false,
        type: Sequelize.DATE,
      },
      updatedAt: {
        allowNull: false,
        type: Sequelize.DATE,
      },
    });
  },

  down: async (queryInterface, Sequelize) => {
    await queryInterface.dropTable('Users');
  }
};

This file creates a Users table and defines how to roll back by dropping it.

What command do I use to run the rollback?

You can run the rollback command using the Sequelize CLI. Just execute:

npx sequelize-cli db:migrate:undo

This will undo the last migration that was applied.