How to implement guide with asp.net core web api returning 500 internal server scenarios when querying related entities
I'm performance testing and I've spent hours debugging this and I'm currently working on an ASP.NET Core 6.0 Web API that involves querying data from a SQL Server database using Entity Framework Core. I've set up EF Core with a one-to-many relationship between two entities: `Order` and `OrderItem`. When I attempt to retrieve an order along with its items using a GET request, I'm getting a 500 Internal Server behavior. Here’s the specific query I'm using in my controller: ```csharp [HttpGet("{id}")] public async Task<ActionResult<Order>> GetOrderById(int id) { var order = await _context.Orders.Include(o => o.OrderItems).FirstOrDefaultAsync(o => o.Id == id); if (order == null) { return NotFound(); } return order; } ``` I've verified that the database context `_context` is being injected correctly and that the `Order` entity is set up as follows: ```csharp public class Order { public int Id { get; set; } public string CustomerName { get; set; } public ICollection<OrderItem> OrderItems { get; set; } } public class OrderItem { public int Id { get; set; } public int OrderId { get; set; } public string ProductName { get; set; } public Order Order { get; set; } } ``` When I debug the application, the behavior is thrown when attempting to include the related `OrderItems`. The exception message I receive is: ``` System.InvalidOperationException: The 'OrderItems' navigation property is not loaded. This is because the query is not being tracked. ``` I have tried several things to fix this scenario: - Ensured that the necessary migrations are applied and the database schema is up-to-date. - Checked if lazy loading is set up correctly in my `DbContext` (it’s currently disabled, as I'm using eager loading with `Include`). - Verified that the API request is being made correctly and that the `id` parameter is valid. I’m at a loss as to why I’m working with this scenario when querying the related data. Any insights or suggestions on how to resolve this would be greatly appreciated! This is part of a larger application I'm building. For reference, this is a production mobile app. Is there a simpler solution I'm overlooking? I'm working in a Debian environment. Thanks for taking the time to read this!