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‫So in the last lecture, we learned about

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‫Mongoose schemas and models,

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‫and so let's now implement a very simple

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‫schema and model for our application.

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‫And for now, let's do that right here

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‫in our server.js file.

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‫Later, of course, we're gonna move

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‫that into a different file.

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‫So, Mongoose is all about models,

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‫and a model is like a blueprint

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‫that we use to create documents.

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‫So it's a bit like classes in JavaScript,

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‫which we also kind of use as blueprints

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‫in order to create objects out of them, right?

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‫So again, we create a model in Mongoose

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‫in order to create documents using it,

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‫and also to query update and delete these documents.

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‫So basically, to perform each of the CRUD operation,

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‫so create, read, update, and delete,

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‫we need a Mongoose model, and in order to

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‫create a model, we actually need a schema.

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‫So, we actually create models out of

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‫Mongoose schema just like we learned

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‫in the last video, and we use the schema

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‫to describe our data, to set default values,

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‫to validate the data, and all kinds of stuff like that.

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‫So just as you will see right now,

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‫because now we're actually gonna start creating

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‫a very simple schema for our tours.

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‫So, let's say tourSchema

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‫is a new mongoose.Schema.

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‫Add that in here we actually pass our schema as an object.

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‫All right, we can then also pass in some options

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‫into the schema, but I'm leaving that to a future video

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‫where we actually need that feature.

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‫So, remember the tour documents that we used

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‫to create in the last section when

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‫we started exploring Mongoose DB?

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‫So we always gave them a name,

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‫a rating and a price, right,

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‫and so let's now replicate that here

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‫by saying name, and then describing

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‫what type of data we want after name,

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‫and we want it to be a string.

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‫So Mongoose actually uses the native

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‫JavaScript data types, and so here we can say string,

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‫or after rating we can say that we want a number

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‫and the same as the price.

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‫It should also be a number, right?

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‫So this is the most basic way of describing our data.

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‫So we have a name, a rating, and a price,

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‫and we specified the data type

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‫that we expect for each of these fields.

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‫So again, this is the most basic way

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‫of describing a schema, but we can take it

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‫one step further by defining something called

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‫schema type options for each field,

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‫or only for some specific field.

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‫So let's start here with the name,

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‫and instead of just specifying it

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‫as a string, let's actually pass in another object.

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‫And so now, we say that we want the type

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‫to be string but we can now

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‫define a couple more options, okay?

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‫For example, we can say that this field is required,

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‫and so we simply set

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‫the required property here to true, all right?

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‫So again, this object here are the schema type options,

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‫and they can be different for different types,

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‫for example the number type has some different

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‫schema options than the string here,

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‫but many of them are also similar.

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‫So for example, the required, we can use it

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‫on number as well, and so let's do that here.

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‫So the type, we still want it to be a number,

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‫and we also want it to be required, okay?

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‫Now, here in the required we can actually

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‫specify the error that we want to be displayed

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‫when we're missing this field.

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‫So, in order to do that we just have to

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‫pass in an array, and the first one is true.

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‫So the first element is true, and the second one

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‫is the error string.

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‫Let's say, a tour must have a name,

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‫and then here let's do the same.

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‫The tour must have a price, okay?

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‫Then we can also set default values

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‫and let's do that here for the rating.

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‫So again, I'm gonna specify some

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‫schema type options here, which is not mandatory,

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‫so it's enough to simply define

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‫the type here like we did, but if you want

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‫some more features, then we need to to at least

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‫specify the schema type options object.

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‫Okay, and then we need to specify the type again,

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‫which is number, and as a default, I want it to be 4.5.

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‫And so if we'd now create a new tour document

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‫using this schema and not specifying the rating,

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‫it would then automatically be set to 4.5, all right?

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‫And just to finish, let's try another one here,

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‫which is to say that the name should be unique.

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‫So, unique and set it to true,

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‫and so like this, we can now have two

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‫tour documents with the same name, all right?

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‫So, this is our very basic schema,

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‫let's now go ahead and actually

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‫create a model out of it, all right?

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‫And that's very simple,

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‫we simply create a variable called Tour,

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‫and then mongoose.model,

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‫then the name of the model, which is Tour with an uppercase

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‫T here, all right.

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‫And so that's just kind of a convention

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‫in programming to always use uppercase

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‫on model names and variables.

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‫So here it's the same, so I also created

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‫this tour variable here with a capital T

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‫just so we know that we're dealing with a model here.

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‫All right, so the name of the model

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‫and then the schema, and that's it.

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‫So just like this, we created a tour

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‫out of the schema that we created here in the beginning.

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‫All right, and so in the next video

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‫we're gonna then use this model here

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‫in order to create our very first tour document, all right?

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‫So just a recap here, we used new mongoose.Schema here

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‫to specify a schema for our data.

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‫So, basically describing it and also doing some validation.

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‫For example, this required here,

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‫this is actually something called a validator

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‫because it is used to validate our data.

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‫In this case, simply to validate

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‫if the name is actually there.

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‫And there are a lot of validators in Mongoose,

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‫and we can actually also create our own,

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‫and so of course we're gonna talk about that

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‫a bit later, again, once we actually need these features.

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‫Anyway, let's now quickly move on

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‫in order to finally start using

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‫the model that we just created.