This repository demonstrates a layered architecture with a repository pattern for data access, combined with GraphQL to expose query and mutation operations. The folder structure clearly separates domain models, data access logic, and GraphQL concerns.

• Models: Domain entities (e.g., Author, Book).
• Repositories: Concrete classes implementing the repository pattern (e.g., AuthorRepository, BookRepository), abstracting data operations.
• GraphQL:
  • Queries (AuthorQuery, BookQuery, etc.) and Mutations (AuthorMutation, BookMutation, etc.) define the read and write operations.
  • Types (AuthorType, BookType, etc.) map domain entities to GraphQL object types.
  • Schemas (AppSchema, AuthorSchema, BookSchema) bring together queries, mutations, and types for different domains.
• Program.cs: Configures services, registers repositories, sets up GraphQL endpoints, and starts the ASP.NET Core application.

1. Repository Pattern

   • Each repository encapsulates data-access logic for a specific entity, promoting loose coupling and easier testing.

2. Layered Structure

   • Domain (Models): Plain C# objects representing business data.
   • Data (Repositories): Handles interaction with the data source.
   • Presentation (GraphQL): Defines GraphQL queries, mutations, and schemas, orchestrating how clients interact with the domain logic.

3. Multiple Schemas

   • Separate schemas for different domains (e.g., AuthorSchema, BookSchema), each exposed via its own endpoint, plus an overarching AppSchema if needed.

4. GraphQL Endpoints

   • Exposes each schema on its own route (e.g., /graphql/author, /graphql/book, /graphql/app).

5. SDL Export

   • The application exports each schema’s SDL (Schema Definition Language) to .graphql files (e.g., Author.graphql, Book.graphql, App.graphql), useful for documentation or integration with other tools.

GraphQL.API ├── GraphQL │ ├── Mutations │ │ ├── AuthorMutation.cs │ │ └── BookMutation.cs │ ├── Queries │ │ ├── AuthorQuery.cs │ │ └── BookQuery.cs │ ├── Types │ │ ├── AuthorType.cs │ │ └── BookType.cs │ └── Schemas │ ├── AuthorSchema.cs │ ├── BookSchema.cs │ └── AppSchema.cs ├── Models │ ├── Author.cs │ └── Book.cs ├── Repositories │ ├── AuthorRepository.cs │ └── BookRepository.cs ├── Program.cs └── README.md

• .NET 9 SDK
• A code editor or IDE (e.g., Visual Studio, VS Code, Rider)

1. Clone the Repository

   git clone https://github.com/{{YourUsername}}/GraphQL.API.git
   cd GraphQL.API
   dotnet restore
   dotnet build
   dotnet run