Express + Sequelize with Relationships (The Sequel)

Objectives

By the end of this, developers should be able to:

• Create Relationships between Sequelize Models
• Add API endpoints to reflect Model Relationships
• Code refactoring with Single Responsibility Principal a.k.a. SRP

Let's Get To Work

Let's create our 2nd Model and update the new model and migration files to make sure they work properly with PostgreSQL.

node_modules/.bin/sequelize model:create --name Article --attributes "title:string, content:text"

Next step, run:

node_modules/.bin/sequelize db:migrate

We should now have our 2nd table created for us.

That's great, but now we have a new table that is empty. Meaning there is nothing to show.

So we will create another seed file to add a few Articles to the Article table.

node_modules/.bin/sequelize seed:create --name articles

Update People Seeder File:

Up:

return queryInterface.bulkInsert('articles', [{
  title: "Hello World!",
  content: "This is a test article.",
  created_at: new Date,
  updated_at: new Date
}], {});

Down:

return queryInterface.bulkDelete('articles', null, {});

With that done, let's seed the db:

node_modules/.bin/sequelize db:seed:all

Let's see what it added to our database.

psql -h localhost -U "postgres" express_api_database_development

\l # List DB
\d # List table
\d # "TABLE_NAME" List Table columns

That's great, now let's finish this by getting the data from the database and showing it to the user like we have already done before.

Solution:

app.get('/api/articles', (req, res) => {
  models.Article.findAll()
    .then(articles => {
      res.status(200).json({ articles: articles });
    })
    .catch(e => console.log(e));
});

Know that we have another real API endpoint that can read from the database and show a list of articles to the user. Let's do another version of it where the user can ask for information about a specific article.

How would we do that?

Solution:

app.get('/api/article/:id', (req, res) => {
  models.Article.findByPk(req.params.id).then(article => {
    res.status(200).json({ article: article });
  })
  .catch(e => console.log(e));
});

Lab

To Do:

1. Update existing Article
2. Delete existing Article