How can I use an ORM query builder in Node.js?

How can I use an ORM query builder in Node.js?

You can use libraries like Sequelize or TypeORM to build queries in Node.js. They provide a fluent API for database operations.

Can you show me an example of a simple query using Sequelize?

Sure! Here's a basic example:

const { Sequelize, DataTypes } = require('sequelize');
const sequelize = new Sequelize('sqlite::memory:');

const User = sequelize.define('User', {
  username: { type: DataTypes.STRING, allowNull: false },
  birthday: { type: DataTypes.DATE }
});

async function createUser() {
  await sequelize.sync();
  const user = await User.create({ username: 'john_doe', birthday: new Date(1990, 1, 1) });
  console.log(user.toJSON());
}
createUser();

What if I want to add conditions to my queries?

You can use the where option in Sequelize. For example:

const users = await User.findAll({ where: { username: 'john_doe' } });

Are there any performance considerations I should be aware of?

Yes, be mindful of N+1 query problems and consider using eager loading with include to optimize performance.