Delve into building a GraphQL endpoint with Deno, compare technologies, configure queries, and integrate PostgresSQL and MongoDB databases to create a secure, high-performing application.

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Deno is a modern and secure runtime for JavaScript. It was created by the same team that created Node.js. Deno offers better performance, security, and simplicity than any other JavaScript runtime.

In this course, you will start by understanding the different technologies used in Deno, such as Typescript. You will compare these technologies with JavaScript and GraphQL as well as learn their terminologies. Then, you will create your own endpoint with Deno and configure queries and mutations in it. Next, you will explore two different databases with Deno: first, you’ll learn how to set up an SQL database using PostgresSQL and then how to configure a NoSQL database using MongoDB to store documents and collections of on-demand data. Finally, you’ll put everything together to have a fully functioning GraphQL endpoint made with Deno and backed by PostgreSQL and MongoDB. 

After this course, you’ll be able to create a Deno application and a GraphQL endpoint while having a database of your choice to store data.

Building a GraphQL Endpoint with Deno

# Data model

To keep it simple, we'll use the same data model we used earlier to define our schema.

We’ll keep all the attributes we had about the book example and add the ability to add some reviews. We’ll add a new entity called `User` to do that. Each user can leave one or more reviews on any book they want. Let’s consider the following updates to our class diagram, where we add the `User` type with only the `firstName` and `lastName` attributes.

# SQL use case

Let’s try to split our data into two databases, one SQL and the other NoSQL. Since our `User` information is usually stable—that is, we can list most of the fields we need right away—we’ll keep our `User` in a SQL database. Some people might also argue that SQL databases are more robust and stable because they follow the ACID property, so any data logic that involves users and authentication should be stored in a SQL database.

## Available options for SQL

We have many options to choose from for our database, like MySQL, Oracle, Postgres, and others. These databases have slight differences overall, but they are more or less identical for our limited use case. We’ll be working with Postgres (but the same applies to most SQL databases).

## SQL syntax
We’ll cover the simple SQL syntax since we won’t be using too much SQL.

Create a table:


Learn how to define a database schema and compare different use cases.

Introduction to Deno, TypeScript, and GraphQL

Creating a Basic GraphQL Endpoint

Databases and Deno

SQL: Postgres and Deno

NoSQL: Mongo and Deno

Wrapping Up

Appendix

Schema and Use Cases

Data model