What is an ORM

Summary

Before diving into the course, let’s briefly cover what an ORM (Object Relational Mapper) is. An ORM abstracts the data layer of your application, allowing you to work with your database as objects in the programming language you’re using—in this case, JavaScript. Whether your database is relational (like PostgreSQL) or non-relational (like MongoDB or Redis), an ORM provides a unified interface for interacting with it.

Instead of writing raw SQL or custom queries, you can use simple methods like User.create(), and the ORM handles the underlying database operations for you. This abstraction is especially helpful in applications that use multiple data stores, as you don’t need to worry about how each one works. Waterline, the ORM used in Sails.js, makes it easy to store, retrieve, and manage data without dealing with the complexities of specific databases.

Transcript

So, before we get into the course in full, let's take a quick moment to talk about what an ORM is. Lately, you can call it an ORM or an ODM because not all databases are relational, especially with the rise of NoSQL databases like MongoDB. An ORM is an acronym for "Object Relational Mapper" or "Object Relational Mapping."

What this means is that, with an ORM, your data layer in your application is abstracted and represented by objects in the language you are writing your software in. For example, in the case of JavaScript, your tables are represented as objects. Or, if you're using something like MongoDB, your documents are represented as JavaScript objects.

I really like this approach because, instead of having to write SQL to access or add data to your database, you have this unified API that makes it easy to quickly retrieve or store data in any database. The ORM makes it so you don’t have to care about which database you’re using at any given time. You could be using a data store like MongoDB, Redis (which is a key-value store), or Postgres.

The ORM won’t care because it gives you a unique, unified interface that provides access. It presents JavaScript objects or methods on those objects. For example, you could use User.create(), and under the hood, the ORM will write the equivalent SQL. But you don’t have to care about that because it’s all abstracted for you.

I find this pretty convenient. It takes the heavy lifting off your plate—you don’t need to craft your own queries or figure out which query works for which database. With an ORM—especially Waterline—you can use more than one datastore in your app without worrying about how those datastores work, because it’s all abstracted for you.

It’s pretty convenient. So that’s what an ORM is. Basically, it’s an abstraction that lets you access your data stores, databases, or document stores as objects. In our case, that means JavaScript objects.