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Get started learning about ORM (Object-Relational Mapping) tools that let you interact with a SQL-based database using JavaScript (instead of raw SQL). In this course, you'll use SQL and Node.js together with the popular ORM, Sequelize. As you learn about Sequelize, you will create and use models for a simple Node.js application.
Sequelize is an ORM library for:
- SQLite
- MySQL
- MariaDB
- PostgreSQL
- Microsoft SQL Server
Resources
Note:
For production-ready applications, you'll want to rely upon a database server platform like PostgreSQL, Oracle, SQL Server, or one of the cloud-based solutions from Amazon, Microsoft, or Google.
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[MUSIC]
0:00
Most Node applications need to talk to
a database at some point to query data or
0:09
create and update specific data.
0:14
While document-based databases like
MongoDB are fairly popular with Node
0:16
developers, SQL-based databases are still
a major component in many applications,
0:20
and at most companies.
0:25
So understanding how to use SQL databases
in a Node.js app is a vital skill to have.
0:26
You've worked with Node and
SQL separately in previous courses.
0:31
So now you maybe asking, well, how does a
database interact with a Node application?
0:34
Are you able to interact with
a database using JavaScript
0:38
instead of having to write
complex raw SQL queries?
0:41
And the answer is you can, with an ORM,
or object-relational mapper.
0:44
I'm Gill,
a JavaScript instructor at Treehouse.
0:48
In this course,
you will learn how to talk or
0:51
connect to a SQL database with Node
using the popular ORM, Sequelize.
0:54
Before we start,
let's first dive into what an ORM is.
0:58
In short, an ORM, again,
1:02
object-relational mapper,
is a tool that lets you, the developer,
1:03
interact with a database, like a SQL
database, using your language of choice.
1:08
No matter what language you're
programming with, whether it's Java,
1:12
Ruby, Python, or JavaScript,
you'll come across
1:15
ORM libraries that allow you to interface
with a SQL database in any given language.
1:18
In our case, we can use JavaScript
instead of raw SQL to create, read,
1:23
update, and delete data in our database.
1:28
Let me show you a simple example.
1:30
In our previous course,
1:32
you wrote SQL queries that may
have looked something like this.
1:34
This query, for example,
1:37
returns all rows in the books table where
a first_published value matches 2000.
1:38
When using an ORM library,
1:44
developers interact with a set of
models to do database operations.
1:46
Instead of interacting
directly with the database,
1:50
by writing raw SQL, for example,
the ORM acts as a mediator
1:53
that oversees the movement of data from
the database to the models and back.
1:56
Using an ORM, the same query in
JavaScript might look like this.
2:01
An ORM executes all the same SQL
queries using your preferred language,
2:05
while abstracting away some of the
complexities of connecting with databases.
2:09
For example,
2:14
Sequelize makes it easy to connect to SQL
databases using plain JavaScript objects.
2:14
Another big advantage of using an ORM with
Node is that being able to write your
2:19
applications using one language instead of
two can help speed up development time.
2:24
Especially for developers who
are not all that fluent in SQL,
2:29
and it can often make managing
data less error-prone.
2:31
Sequelize is a popular and
well maintained ORM library
2:34
that provides built-in queries and
key functionality to help you maintain and
2:37
interact with databases,
including the creation of tables,
2:41
all the CRUD operations, and
the ability to validate user input.
2:45
In theory, using an ORM like Sequelize
makes your life as a developer easier.
2:49
Now, when you're used to interacting
with the database directly by writing
2:53
SQL queries, there is a learning curve to
familiarize yourself with how Sequelize or
2:56
any ORM handles interacting
with the database.
3:01
But once you're comfortable
with the ORM's terminology and
3:04
API, it's generally a time-saver.
3:06
For our database,
we'll use SQLite, a simple,
3:09
easy to use relational database that
doesn't require you to install or
3:12
configure anything on your system
in order to make use of it.
3:15
This makes it an ideal database for
learning projects.
3:18
As you learn about the Sequelize ORM,
you'll create and use models for
3:21
a simple Note application.
3:24
Imagine that you've been tasked with
creating an application like IMDB
3:26
that will allow users
to view listed movies.
3:30
The models that you create
will represent movies and
3:33
the people who create and/or
star in those movies.
3:36
By the end of this course,
you'll have learned how to install and
3:39
configure the Sequelize ORM,
define Sequelize models,
3:43
perform CRUD operations using
Sequelize models, and more.
3:46
To get the most from this course,
you should be familiar with Node and NPM.
3:50
Sequelize is a promise-based ORM.
3:53
So if you're not familiar with
JavaScript promises and async/await, or
3:56
need a refresher, check the links posted
in the teacher's notes with this video.
3:59
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