GraphQL is a query language for APIs with this client can define what they need and server get exactly that, nothing more and nothing less.

getting started with Node js and graph ql 2-01.png

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GraphQL is a query language for web APIs and a runtime for fulfilling queries with existing data. GraphQL gives clients the power to ask for precisely what they need, making it easy to evolve APIs with powerful developer tools.

This course is an introduction to GraphQL using the Node.js JavaScript runtime environment and Apollo Server. You’ll start with an introduction to GraphQL’s architecture and functions before exploring the structure of GraphQL data and learning to perform meaningful, complex queries. You’ll then learn how to update server data using mutations. Next, you’ll explore the GraphQL type system and schemas to set up a GraphQL server using Apollo Server. Once the server is set up, you’ll implement a full GraphQL application using Apollo and Node.js.

By the end of this course, you’ll have a rich understanding of GraphQL’s architecture and methodology and be prepared to deploy GraphQL applications to the web using Apollo and Node.js.

Getting Started with GraphQL using Node.js

Which types aren’t part of the introspection system?


Which types aren’t part of the introspection system?

```
query (
  $greekPizza: String!
  $detroitPizza: String!
){
  greekPizza: pizzas(pizza: $greekPizza) {
    ...PizzaFragment
  }
  detroitPizza: pizzas(pizza: $detroitPizza) {
    ...PizzaFragment
  }
}

fragment PizzaFragment on Pizza{
  id
  pizza
}
```

```
{
  schema {
    types {
      name
    }
  }
}
```

```
{
  __schema {
    mutationType  {
      name
      fields {
        name
        args {
          name
          type {
            kind
            name
          }
        }
        type {
          kind
          name
        }
      }
    } 
  }
}
```

Which query is valid for querying schema information?


Which query is valid for querying schema information?

```
{
  "data": {
    "__schema": {
      "queryType": {
        "name": "Query",
        "fields": [
          {
            "name": "pizzas",
            "args": [
              {
                "name": "pizza",
                "type": {
                  "kind": "SCALAR",
                  "name": "String"
                }
              }
            ],
            "type": {
              "kind": "LIST",
              "name": null
            }
          },
          {
            "name": "pizza",
            "args": [
              {
                "name": "id",
                "type": {
                  "kind": "SCALAR",
                  "name": "Int"
                }
              }
            ],
            "type": {
              "kind": "NON_NULL",
              "name": null
            }
          }
        ]
      }
    }
  }
}
```

```
{
  "data": {
    "__schema": {
      "types": [
        {
          "name": "PizzaStatus"
        },
        {
          "name": "Pizza"
        },
        {
          "name": "Int"
        },
        {
          "name": "String"
        },
        {
          "name": "Topping"
        },
        {
          "name": "ToppingInput"
        },
        {
          "name": "Query"
        },
        {
          "name": "Mutation"
        },
        {
          "name": "Boolean"
        },
        {
          "name": "__Schema"
        },
        {
          "name": "__Type"
        },
        {
          "name": "__TypeKind"
        },
        {
          "name": "__Field"
        },
        {
          "name": "__InputValue"
        },
        {
          "name": "__EnumValue"
        },
        {
          "name": "__Directive"
        },
        {
          "name": "__DirectiveLocation"
        }
      ]
    }
  }
}
```

```
{
  "data": {
    "__schema": {
      "mutationType": {
        "name": "Mutation",
        "fields": [
          {
            "name": "createPizza",
            "args": [
              {
                "name": "pizza",
                "type": {
                  "kind": "SCALAR",
                  "name": "String"
                }
              },
              {
                "name": "toppings",
                "type": {
                  "kind": "NON_NULL",
                  "name": null
                }
              }
            ],
            "type": {
              "kind": "NON_NULL",
              "name": null
            }
          },
          {
            "name": "updatePizza",
            "args": [
              {
                "name": "id",
                "type": {
                  "kind": "NON_NULL",
                  "name": null
                }
              },
              {
                "name": "pizza",
                "type": {
                  "kind": "SCALAR",
                  "name": "String"
                }
              },
              {
                "name": "toppings",
                "type": {
                  "kind": "LIST",
                  "name": null
                }
              }
            ],
            "type": {
              "kind": "NON_NULL",
              "name": null
            }
          }
        ]
      }
    }
  }
}
```

What's the result of the GraphQL query below?
```
{
  __schema {
    types {
      name
    }
  }
}
```

What’s the result of the GraphQL query below?
<pre><code>{
 __schema {
 types {
 name
 }
 }
}
</code></pre>

Test your understanding of schema introspection.

Introduction

Getting to Know GraphQL

Queries

Mutations

Schemas and Types

Schema Validation

Schema Execution

Schema Introspection

GraphQL Best Practices

GraphQL Exam

Quiz on Schema Introspection