Basics
GraphQL Syntax
GraphQL Syntax Basics
GraphQL syntax uses queries and mutations with type definitions.
Introduction to GraphQL Syntax
GraphQL is a query language for APIs that allows clients to request only the data they need. Unlike REST, which requires multiple endpoints for different resources, GraphQL provides a single endpoint to query and mutate data. Understanding the syntax is the first step in mastering GraphQL.
GraphQL Queries
Queries are used to request data from a GraphQL server. Each query specifies the fields and objects you want to retrieve. Here is a basic example of a query that fetches a user's name and email:
GraphQL Mutations
Mutations are similar to queries, but they are used to modify data on the server. They can create, update, or delete data. Below is an example of a mutation that creates a new user:
Type Definitions
Type definitions in GraphQL define the shape of the data that can be queried or mutated. They are written in the Schema Definition Language (SDL). Here is an example of a simple type definition for a user:
Understanding Fields and Arguments
Each field in a GraphQL query can have zero or more arguments. These arguments allow you to pass additional data to the field. For example, in the user query, the id argument specifies which user to retrieve:
Non-Null and List Types
GraphQL allows you to define non-nullable types using an exclamation mark (!) and list types using square brackets ([]). Non-nullable types guarantee that a field will always return a value, while list types indicate that the field returns an array of values.
