WEBVTT

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Hi everyone.

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Let's talk about the DTO, or we can say "data transfer object".

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So what is the data transfer object?

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It's just a dumb object.

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Okay, we can say it's just a "dumb object".

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The only purpose of the data transfer object a reduced amount of data.

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Okay, that's the first purpose will be reduce the data.

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And in the MVC architecture, we usually write the validation logic inside the data transfer object.

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Now first forget that.

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Let me show you what is the reduced data right now.

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Right now you can see, for example, I have a schema like this id username, email and password.

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Now lets think about how we can create the data like this.

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In order to create we don't need the the "id" right?

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The "id" is useless in this case.

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We don't need the ID when we.

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Create the data, right?

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For that reason, if we use the DTO, it will reduce the data.

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It means we will remove the "id" when we create the "dump object".

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Based on the original object.

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Okay.

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That the first one.

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And the second one.

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Now let's think about how the data can be response.

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For example, when we create the data right here and the server will response for you the data, we don't

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need the password, right?

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We don't need

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The password.

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And it's also "reduce" the data, right? Here and here.

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We will call that the "DTO" -> data transfer object.

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And we need two data transfer object for create and for response.

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Right.

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And that's the idea.

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Of DTO.

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And when clients send this amount of data into the server we usually send the "DTO" over server okay.

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And server it will return the "DTO" also.

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And we will validation inside the DTO.

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Also.

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Let me see how we can do that right now.

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If you scroll down inside the Mongo option right here, Let me see.

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That you know it's not right here.

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I will scroll up a little bit.

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Here.

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Right here.

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You can see it.

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DTO, right?

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This is the "Cat DTO"

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And let me show you how we can do that in here in the post.

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I will create the "dto".

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I think  "dtos" is the best way.

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Okay.

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And I will create.

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One "dto" will be "create-post"

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post.dto.ts

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Right.

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And this is just the "dumb object" or "dumb class" based on the original class.

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The original class will be the "post", right?

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And now let me export class "CreatePostDTO"

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And in here, what we have, we have a title will be string and the description is string.

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Well, the reason, the reason it is the same property because we don't have so much property in the

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post

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So this is not important.

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This case.

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But later when we work with user we will understand more about that.

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Okay that's the first one.

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And because we already use that, we will use inside the controller and service. In the controller right here

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The "requestBody", I will use the "CreatePostDTO" and the body right here, I will use

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CreatePostDTO

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CreatePostDTO okay, that the first look.

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About

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DTO it's just a data type right now

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And the application will work if you see.

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Okay.

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But for example if I remove the title let's see what happened.

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It will create this.

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Right?

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I don't want that I want it.

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Show the error.

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Show how I can do that.

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And in the next video I will show you how we can validation.

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I will see you in the next one.