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GraphQL Notes

November 25, 2024
graphql
Structure of GraphQL project, schema, types, queries, etc.
Table of Contents

Introduction to GraphQL​

tip

The GraphQL docs are actually excellent and provide good code samples, so i'm not going to duplicate my own code samples here. Instead I will link to relevant documentation pages when possible.

What is GraphQL?​

  • A query language for APIs and a runtime for executing those queries.
  • Developed internally by Facebook in 2012 and released publicly in 2015.

Why Use GraphQL Over REST?​

  • Flexibility: Clients can specify exactly what data they need.
  • Efficiency: Reduces over-fetching and under-fetching of data.
  • Strong Typing: Schema defines types and relationships in your data.

Core Concepts​

Schema​

  • The heart of any GraphQL server; defines types and their relationships.
  • Written using GraphQL Schema Definition Language (SDL).

GraphQL > Learn > Schemas and Types

Apollo GraphQL > Tutorials > Schema Definition Language (SDL)

Types​

  • Scalar Types: Int, Float, String, Boolean, ID.
  • Object Types: Custom types defined by the schema.
  • Enumeration Types: A special kind of scalar that is restricted to a particular set of allowed values.

GraphQL > Learn > Schemas and Types

Queries​

  • Read-only fetches to retrieve data.
  • Clients specify exactly what they need.

GraphQL > Learn > Queries

Mutations​

  • Operations that modify data on the server.
  • Similar to queries but used for Create, Update, Delete actions.

GraphQL > Learn > Mutations

Subscriptions​

  • Allows clients to subscribe to real-time updates.
  • Uses WebSockets to maintain a persistent connection.

GraphQL > Learn > Subscriptions

Resolvers​

  • Functions that resolve a value for a type or field in the schema.
  • Connects schema fields to underlying data sources.

GraphQL > Learn > Execution

Apollo > Docs > Resolvers

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