What are some examples of using Sequelize with Node.js?

What are some examples of using Sequelize with Node.js?

Sequelize is a promise-based Node.js ORM for SQL databases. Here are a few examples:

1. Connecting to a Database: You can connect to a PostgreSQL database using Sequelize like this:

   const { Sequelize } = require('sequelize');
   const sequelize = new Sequelize('database', 'username', 'password', {
     host: 'localhost',
     dialect: 'postgres',
   });
   

2. Defining a Model: You can define a model for a 'User' like this:

   const User = sequelize.define('User', {
     username: {
       type: Sequelize.STRING,
       allowNull: false,
     },
     password: {
       type: Sequelize.STRING,
       allowNull: false,
     },
   });
   

3. Creating a Record: To create a new user record:

   User.create({ username: 'john_doe', password: 'securepassword' });
   

These are just a few examples to get you started!

Can you show me how to query data using Sequelize?

Certainly! To query data using Sequelize, you can use methods like findAll, findOne, or findByPk. Here’s an example:

User.findAll().then(users => {
  console.log(users);
});

This will retrieve all users from the database. If you want to find a user by their primary key:

User.findByPk(1).then(user => {
  console.log(user);
});

This retrieves the user with an ID of 1.

How do I update a record in Sequelize?

To update a record in Sequelize, you can use the update method. Here’s an example:

User.update({ password: 'newpassword' }, {
  where: { username: 'john_doe' }
});

This will update the password for the user with the username 'john_doe'.

What about deleting a record?

To delete a record, you can use the destroy method. For example:

User.destroy({
  where: { username: 'john_doe' }
});

This will delete the user with the username 'john_doe' from the database.