What does a GraphQL schema define?

What does a GraphQL schema define?

• A. It defines only the operations available to the client.
• B. It describes how data is stored in the database.
• C. It is used to authenticate clients.
• D. It defines data types and relationships, enabling nested traversal in a single query.

Answer: (D)

A GraphQL schema defines the shape of the data: the object types, their fields, and how those types relate to one another. This type system lets clients request exactly what they need and traverse nested relationships in a single query, because a field on one type can reference another type and be resolved into related data. The schema also specifies the root entry points (like queries and mutations) and what fields are available on each type. It doesn’t dictate how data is stored in a database or handle authentication by itself—the data storage is handled by the backend and resolvers, and authentication is typically managed at the network layer or through middleware (though you can express access rules where supported). The other options describe narrower aspects and miss the core idea that the schema defines the data shapes and their connections enabling deep, single-request retrieval.

A GraphQL schema defines the shape of the data: the object types, their fields, and how those types relate to one another. This type system lets clients request exactly what they need and traverse nested relationships in a single query, because a field on one type can reference another type and be resolved into related data. The schema also specifies the root entry points (like queries and mutations) and what fields are available on each type. It doesn’t dictate how data is stored in a database or handle authentication by itself—the data storage is handled by the backend and resolvers, and authentication is typically managed at the network layer or through middleware (though you can express access rules where supported). The other options describe narrower aspects and miss the core idea that the schema defines the data shapes and their connections enabling deep, single-request retrieval.