VideoGameApi

ASP.NET Core Web API (.NET 9) for managing video games. Data is persisted in SQL Server with Entity Framework Core (code-first migrations and seed data).

Learning guide: CONCEPTS.md — explanations of every C#, .NET, and EF Core concept used in this project, with a senior-developer revisit section and study checklist.

What we built

1. VideoGame model — Id, Title, Platform, Developer, Publisher
2. Entity Framework Core + SQL Server — VideoGameDbContext registered in Program.cs
3. Code-first migrations — create/update the VideoGameDb database from the model
4. Seed data — sample games configured with HasData in OnModelCreating
5. CRUD endpoints — controller uses EF Core against the database (not an in-memory list)
6. API docs — OpenAPI + Scalar in Development
7. .gitignore — standard ignores for .NET build/IDE artifacts

Prerequisites

• .NET 9 SDK
• SQL Server Express (local instance: localhost\SQLExpress)
• EF Core tools (Package Manager Console in Visual Studio, or dotnet ef)

Configuration

Connection string in appsettings.json:

"ConnectionStrings": {
  "DefaultConnection": "Server=localhost\\SQLExpress;Database=VideoGameDb;Trusted_Connection=true;TrustServerCertificate=true;"
}

Database migrations

From Package Manager Console (default project: this API):

Add-Migration Initial
Update-Database

# After adding/changing HasData seed configuration:
Add-Migration SeedData
Update-Database

Or with the .NET CLI (requires dotnet-ef):

dotnet ef migrations add Initial
dotnet ef database update

Verify data in SQL

sqlcmd -S localhost\SQLExpress -E -d VideoGameDb -Q "SELECT Id, Title, Platform FROM VideoGames"

Or in SSMS: connect to localhost\SQLExpress → database VideoGameDb → table dbo.VideoGames → Select Top 1000 Rows.

Run the project

dotnet run

• HTTP: http://localhost:5139
• HTTPS: https://localhost:7018
• Scalar UI: https://localhost:7018/scalar/v1

API endpoints

Base path: /api/VideoGame

Method	Endpoint	Description	Success
GET	/api/VideoGame	Get all video games	200 OK
GET	/api/VideoGame/{id}	Get one video game by id	200 OK
POST	/api/VideoGame	Create a video game (Id from SQL identity)	201 Created
PUT	/api/VideoGame/{id}	Update an existing video game	204 No Content
DELETE	/api/VideoGame/{id}	Delete a video game	204 No Content

Missing ids return 404 Not Found. Changes are saved to SQL Server and persist across restarts.

Example — create

POST /api/VideoGame

{
  "title": "God of War Ragnarök",
  "platform": "PS5",
  "developer": "Santa Monica Studio",
  "publisher": "Sony Interactive Entertainment"
}

Example — update

PUT /api/VideoGame/1

{
  "title": "Spider-Man 2 Remastered",
  "platform": "PS5",
  "developer": "Insomniac Games",
  "publisher": "Sony Interactive Entertainment"
}

You can also try the requests in VideoGameApi.http.

Project layout

VideoGameApi/
├── Controllers/
│   └── VideoGameController.cs   # EF Core CRUD actions
├── Data/
│   └── VideoGameDbContext.cs    # DbContext + HasData seeding
├── Migrations/                  # EF migration files (keep in source control)
├── VideoGame.cs                 # Model
├── Program.cs                   # DI, DbContext, OpenAPI, Scalar
├── appsettings.json             # SQL Server connection string
├── VideoGameApi.http            # Sample HTTP requests
├── .gitignore
├── README.md
└── CONCEPTS.md                 # Study guide for concepts used in this project

Notes

• CRUD uses VideoGameDbContext with async EF Core APIs (ToListAsync, FindAsync, SaveChangesAsync).
• Seed data lives in VideoGameDbContext.OnModelCreating via HasData. Add a new migration after changing seeds, then run Update-Database.
• Do not delete the Migrations folder after generating migrations.
• Scalar and OpenAPI are enabled only when ASPNETCORE_ENVIRONMENT is Development.