GraphQL Tutorial #7 - GraphQL Schema

so then we know we have to make a schema to describe how the date on our graph will look so let's make that schema now inside server I'll make a new folder and I'm gonna call this said schema and inside that will create a file and we're also going to call this schema Jas all right so the first thing we need to do inside this file is require graph QL that's the main graph QL package we installed in the last video so we'll say Const graph QL is equal to require and then graph queue up all right so in this file is where we're going to define our schema remember our schema will describe the data on this kind of graph it describes the object types the relations between those object types and it describes how we can reach into the graph to interact with that data whether that be to query it and retrieve data or to mutate or change the data so either way we're jumping into this graph to interact with it right so we'll start off by inside this schema describing the object types we want on our graph so the graph right here is going to have two object types on it books and authors so ultimately we need to describe these two object types in the schema file and the relationship between them and also how to query these object types to get data buck so we're just going to start off with one object type to begin with the book so the way we define object types in graph QL is a little bit unusual at first what we need to do is we need to grab something from this graph cue our package to do it so I'm gonna say Const and I'm going to use a bit of es6 destructor in here which allows us to grab a variables out of something else so I'm going to require or not require destructor graph QL object type and pay attention to the capitalization here capital ql o and c alright that's really important so I'll set that equal their graph QL so this D structure and what it's going to do is grab this variable of this function for us from this thing right here from this package we're taking it out and storing it now so we can use this inside this file alright so once we've done that we can now define a new type so we'll call this type a book type and we'll set this equal to a new grass ql object type alright so that's the thing we've just grabbed right here so this right here is a function which takes in a object and this object is going to define what this book type is all about so first of all we'll give this a name I'm going to call it book and then we need to also define the fields on this object type so remember the fields are going to be things like a name property genre an ID that kind of thing so this fields property is actually going to be a function so we'll do our parentheses and then an arrow then another parenthesis and then an object inside that now the reason this needs to be a function is because later on when we have multiple types and they have references to one another then unless we wrap those fields in a function one type might not necessarily know what I know the type is does that make sense it might not a minute but later on when we introduce all the types as well I'll explain this a little bit more and why we need it and I'll show you what happens if we don't wrap it in a function all right so this right here this function is going to turn this object and we need to define our different fields inside here so first of all the ID the ID is going to be maybe a string of random numbers or something like that so when we're defining these fields we need to say what type is is it a string is he an integer or some other type so we'll open up an object and we're going to say the type is going to be something now we can't just do string again this is one of the nuances of graph QL we have to use a special string a graph QL string in order for it to understand the type so again we're going to grab that from graph QL by doing a comma and then saying graph QL string so again with destructor in here and we're grabbing this thing from this package as well so now we have access to this in this file so the type of this ID is going to be a graph QL string all right so a string of seemingly random numbers or something like that so that's one field that we're gonna have on each book what is another field the name of the book so again we need to define a type for this and it will be a string again so we'll say graph keep our string for this and then finally we'll have a genre property and again this will be of type string so we'll say graph QL string for that one as well so right now what we've done is we've defined our first object type on this graph and it's a book type it's called book and it has these fields right here an ID name and genre and that all of type graph QR string this is graph QL saying okay I'm expecting a string for this type and this type and this type okay so all three of them and we've wrapped all of those fields inside a function and es6 function which is returning this object and again that's because when we have multiple types later on this is going to help overcome any kind of reference errors all right and we'll explore that a little bit more when we have multiple types so this book type here is a first step in defining our our graph we'll look we've said that on a graph we're going to have this object type which is a book right but this is just one part of our schema based on this diagram down here remember we have other things in here an author type we also have these connections between the different objects and we have these entry points as well where we jump into the graph so this thing right here is a good first step but it is just the first step in defining our whole ski remember ultimately we want to pass all of this schema into this thing right here all right so we've started to define this in the next tutorial what we're going to do is we're going to look at our entry points into the graph so that we can query this data these are called rip queries and we'll take a look at those in the very next tutorial