How do I handle migrations in Node.js ORMs?

How do I handle migrations in Node.js ORMs?

Handling migrations in Node.js ORMs typically involves using built-in migration tools or libraries. For example, if you're using Sequelize, you can create migration files using the CLI and run them to update your database schema.

Can you give me an example of a migration file in Sequelize?

Sure! A simple migration file in Sequelize might look like this:

'use strict';

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

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

This file creates a 'Users' table with some basic fields.

What if I want to roll back a migration?

To roll back a migration in Sequelize, you can use the command sequelize db:migrate:undo. This will execute the down method in your migration file, reverting the changes made by the up method.