GraphQL with NestJS
Apollo Server, resolvers, schemas, queries, mutations, subscriptions, data loaders
1What is GraphQL?
What is GraphQL?
답변
GraphQL is a query language for APIs developed by Facebook, allowing clients to request exactly the data they need. Unlike REST where each endpoint returns a fixed structure, GraphQL provides a single entry point with a strongly typed schema. This approach reduces over-fetching and under-fetching of data while improving application performance.
2What is the main role of a GraphQL schema?
What is the main role of a GraphQL schema?
답변
The GraphQL schema defines the complete API structure by specifying available data types, queries, mutations, and relationships between entities. It serves as a contract between client and server, enabling automatic query validation and autocomplete in development tools. The schema uses Schema Definition Language (SDL) to declaratively describe types and their fields.
3What is the difference between Query and Mutation?
What is the difference between Query and Mutation?
답변
Queries are used to read data without modifying server state, while Mutations are used to create, update or delete data. This semantic distinction helps understand an operation's intent and allows the server to apply specific optimizations. By convention, Queries can be executed in parallel, while Mutations are executed sequentially to ensure data consistency.
What is a resolver in GraphQL?
Which NestJS decorator defines a GraphQL Query?
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