Rule Definition
Using .Include() to load many or deep navigation properties: - Generates large SQL JOINs - Increases query complexity and size - Causes duplication in result sets (Cartesian explosion) - Wastes memory by loading unnecessary data This leads to significant performance issues, especially when loading related collections (1:N or N:N relationships).

Remediation
Only load what you actually need. Don’t include navigation properties unless they are required by your logic or UI. You can also project to a DTO.

Violation Code Sample

var order = dbContext.Orders
    .Include(o => o.Customer)
    .Include(o => o.ShippingAddress)
    .Include(o => o.OrderLines)
    .Include(o => o.Payments)                 // ⚠️ VIOLATION : use of multiple Include()
    .FirstOrDefault(o => o.Id == id);

Fixed Code Sample

// Load necessary
var order = dbContext.Orders
    .Include(o => o.OrderLines)               // ✓ FIXED : only one .Include()
    .FirstOrDefault(o => o.Id == id);

// Or project to a DTO

var order = dbContext.Orders
    .Where(o => o.Id == id)
    .Select(o => new OrderDto {               // ✓ FIXED : projection to a DTO
        Id = o.Id,
        Total = o.Total,
        CustomerName = o.Customer.Name
    }).FirstOrDefault();

https://learn.microsoft.com/en-us/ef/core/querying/related-data/eager https://learn.microsoft.com/en-us/ef/core/querying/single-split-queries https://learn.microsoft.com/en-us/ef/core/performance/