This is the transcript of a video i watched "Presenter: In this video,

I'm going to give you an overview of Hibernate and JPA.

We'll cover the following topics.

First off, we'll answer the question, what is Hibernate?

Then we'll go through

and look at the benefits of using Hibernate.

We'll also find out what is JPA,

and also look at the benefits of using JPA.

And, finally, I'll show you some real quick code snippets

on how to make use of JPA in your application.

All right, first off, what is Hibernate?

Hibernate is a framework for persisting

or saving Java objects into a database,

it's a very popular framework

that's used by a lot of enterprise Java projects.

Basically, at a very high level

you'll have your Java application,

it'll make use of this Hibernate framework,

and you can use it for saving and retrieving data

from the database.

Now, what are the benefits of using Hibernate?

Well, Hibernate handles all of the low level SQL code,

so it actually minimizes the amount of

JDBC code that you have to develop.

Hibernate can handle the Object-to-Relational mapping,

and it makes it really easy to create apps

to store and retrieve objects from the database.

Well, how does it work?

Again, Hibernate provides something

called the Object-to-Relational mapping,

or you'll hear the buzzword or keyword called ORM.

As a developer, all you need to do is

tell Hibernate how your Java class or object

maps to the data in the database.

In fact, you'll map your Java class

to a given database table.

In this example, on the far left we have our Java class,

that's a student,

it has four fields, ID, first name, last name, and email;

and notice how the field's first name and last name

are spelled using CamelCase.

We have the Hibernate framework in the middle,

and on the far right we have the actual database table.

In this example, we have a table called Student.

It has ID, which is the primary key,

and there's the first name and last name,

and note its first underscored name

and last underscored name.

And then we also have a field for email address.

And what we'll do here is that this Java class

will map to this given table,

and we set up the one-to-one mapping between the fields

and the actual columns in the database.

You can set up this mapping

via a configuration file using XML,

or using Java annotations,

in this course will make use of Java annotations,

and I'll cover those technical details

in some of the upcoming videos.

Now, what is JPA?

JPA is the Jakarta Persistence API,

previously known as the Java Persistence API.

It's the standard API

for Object-to-Relational mapping, or ORM,

it's only a specification, defines a set of interfaces,

and it requires an implementation to be usable.

Now let's take a look at some JPA vendor implementations.

So we start with the JPA spec,

it's just a list of interfaces,

and we need an implementation.

One implementation here is Hibernate.

just like with Java coding, they take those interfaces

and they provide an implementation

of those given interfaces.

And then there's another implementation here, EclipseLink.

Again, they have their own implementation

of the JPA specification.

Now, there are other JPA vendors out there,

you can go to the site here at love2code.com/jpa-vendors,

and I'll give you a list of those

JPA vendors that are out there.

But I'll go ahead and tell you

that Hibernate is probably the most popular implementation

of the JPA specification,

and it's also the default implementation

used in Spring Boot.

Now, what are the benefits of using JPA?

By having a standard API

you're not locked into the vendor's implementation,

so you can maintain portable, flexible code

by simply coding to the JPA spec or the interfaces.

So, theoretically, you can switch vendor implementations.

For example, if vendor ABC stops supporting their product,

then you could switch to vendor XYZ

without any vendor lock-in, which is a good thing.

And the reason for this is

because you're coding to the actual JPA specification

or the standard API.

Let's take a look at a scenario here

of swapping vendor implementations.

We have our application, My Biz App,

that's the code that we're creating,

and we're writing our DAO code based on the JPA spec.

In version one of our project we're using EclipseLink,

and then maybe for version two of our project

we wanna move to a different implementation.

Again, I'm totally making this up,

but say, for example, EclipseLink is no longer around

or there are some issues

with that given vendor implementation.

Well, we can easily swap in

another JPA vendor implementation,

and we can swap in Hibernate.

So it's there up and running,

and we pretty much have minimal code changes to make

because we're writing code to the standard specification.

We simply have to change our configuration

to tell it which vendor implementation to use,

and that's basically it.

So that's the main advantage here of using JPA

of coding to the standard API

for Object-to-Relational mapping.

Okay, great, now let's take a look at a quick example

on how to save a Java object with JPA.

The first thing we do is create the Java object,

and this is just really standard, basic Java here, right?

We simply use the new keyword

and we say New student, Paul Doe,

and we give Paul a give email address.

And that's the first name, last name and email address.

Then we save this object to the database,

and so here we make use of the entityManager,

which is a special JPA object or JPA helper object.

We say entityManager.persist,

and then we pass in our object.

And what happens in the background is

that JPA will take the Java object

based on those mappings that we defined earlier,

and JPA will take that information

and store it in the appropriate table

in the appropriate columns,

and JPA will do all the work for you.

And, really, behind the scenes

Hibernate is an implementation of JPA

so really, really Hibernate would do all the work for you,

but you kinda understand what I'm saying here

at a very high level of talking about JPA.

This is all really good and really simple.

If you remember in the old days of JDBC,

you would have to manually write the SQL code.

So you'd have to manually set those values,

manually execute the SQL statement, and so forth.

But here, JPA, with the help of Hibernate,

does all the work for you in the background,

and I really like this feature.

So, as you can see, it's really simple here

to save a Java object using JPA.

Now that we have something in the database,

how do we retrieve it?

Well, there's a number of different options

on how to retrieve objects,

but I'll show you here a very basic example

by making use of the primary key.

Some of the coding here that you see

is from what we had from the previous slide,

and now I'm gonna use this information

to retrieve data from the database using primary key of one.

And in this example I know that our database was empty

and we knew that the first item

will have the primary key of one,

so I can use this ID.

I'll show you other techniques

on how to retrieve objects later.

Here, I'll make use of this entityManager.find,

and I tell it what I want to get, a Student.class,

and I give the ID or the primary key.

Behind the scenes JPA will say,

"Okay, let me go look at this table called Student,

and let me find the students whose primary key

matches this ID."

It'll find that student object and return it to us,

and that's it.

And that's basically how we retrieve

a Java object from the database.

Okay, so let's look at a scenario where you wanted to say,

"Hey, I wanna retrieve all the students,

not just one student but a list of students."

So that's fine, we can set up a query

and get all of the students.

JPA has a language for queries,

here I'll say entityManager.createQuery from student,

and it'll basically give us a list of

all of those student objects.

And then I can actually retrieve those objects

here from the query by saying theQuery.getResultList.

So behind the scenes it'll do the query for us,

give us a list of objects and then return it,

and that's it, and we can make use of it.

Again, notice we didn't have to do

any low level SQL coding or JDBC coding,

we simply added code here from using this in entityManager,

and we could actually retrieve those objects.

And so here we made use of a very basic query,

actually makes use of something called

the JPA Query Language,

and we'll talk more about this in later videos,

but at a very high level it allows you to query

and it'll give you all the students from a given database.

And you can also set up special wear clauses

using alike conditions, and so on.

I'll share examples of that later on.

All right, so the nice thing to hear is

that I showed you a very high level example here

of using Hibernate JPA, with some real quick code snippets.

In the following videos

we'll get into more technical details

and I'll have separate details,

we'll dive into each one of these topics.

I'll show you how to set up a connection to the database,

how to make use of the JPA EntityManager,

then we'll walk through code examples

for doing call the major CRUD features.

And when I say CRUD I mean create, read, update, and delete,

and we'll cover all of that in the following videos.

And then we'll wrap everything up with a small project

so you can actually see how all of this comes together.

And we'll have a full working example

by the end of the video series,

so we have a lot of good things coming, so I'm excited.

So I'll see 'ya in the next video.". Can you explain it better to me? Keep in mind that I'm an backend dev with expressjs and prisma.