note Select is used to project elements into a sequence

[smiller7812]

Description

In the section: Loading related data with Select,

I am not sure how the Select function really fits into the context of the differences between eager and lazy loading. (I've always been a little fuzzy here. I just always use eager loading when I need a nav prop filled)

But if this example should go here I would explain the fact that the Selection function being used here projects elements of a sequence into a new form be it a view model or a var variable capable of holding an anonymous type.

Your View Model projection example:

public IList CourseVM { get; set; }

public async Task OnGetAsync()
{
    CourseVM = await _context.Courses
    .Select(p => new CourseViewModel
    {
        CourseID = p.CourseID,
        Title = p.Title,
        Credits = p.Credits,
        DepartmentName = p.Department.Name
    }).ToListAsync();
}

My inline anonymous object example:

 var coursesProjected = await _context.Courses
 .Select(p => new 
 {
     CourseID = p.CourseID,
     Title = p.Title,
     Credits = p.Credits,
     DepartmentName = p.Department.Name
 }).ToListAsync();

coursesProjected has to be of type var here to work.

Page URL

https://learn.microsoft.com/en-us/aspnet/core/data/ef-rp/read-related-data?view=aspnetcore-10.0&tabs=visual-studio

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/data/ef-rp/read-related-data.md

Document ID

3cb264da-2ff1-1256-572f-aa4ebca6e255

Platform Id

5d8ba75a-678a-21ac-469c-05e8afe24128

Article author

@tdykstra

Metadata

• ID: d0026f69-7e5d-0d3e-5586-16ecc0656ff0
• PlatformId: 5d8ba75a-678a-21ac-469c-05e8afe24128
• Service: aspnet-core
• Sub-service: data-access

Related Issues

[wadepickett]

@smiller7812, Thanks very much for taking the time to let us know. We will take a look!

[wadepickett]

🤖 AI Triage Summary

📌 Note to community: This is an automated preliminary analysis to help our documentation team quickly review, determine scope and prioritize this issue. This report is not a resolution and all suggestions require team review before implementation.

---

This preliminary assessment report was run by: @wadepickett
Date: 2026-05-21
Issue: 37178
Model: GitHub Copilot

---

Issue Analysis: Clarify that Select projects elements into a new form in "Loading related data with Select" section

✅ Issue Validation

Status: Valid and actionable

📋 Issue Summary

The issue requests that the "Loading related data with Select" section better explain that Select is being used to project elements of a sequence into a new form (a view model or anonymous type), rather than being a loading strategy comparable to eager/lazy loading. The current documentation introduces Select as an "alternative" to Include for loading related data, but doesn't clarify the fundamental difference: Select performs a projection, not a loading strategy per se. The reporter also suggests showing an anonymous type example alongside the existing view model example.

📁 Potentially Affected Files

These files have been identified as possibly related to this issue and may need review.

File	Path	Lines	Section
Main article	aspnetcore/data/ef-rp/read-related-data.md	130-146	"Loading related data with Select" (aspnetcore-5.0+ moniker)
Main article (3.0-5.0)	aspnetcore/data/ef-rp/read-related-data.md	402-418	"Loading related data with Select" (aspnetcore-3.0 moniker)
Code sample	aspnetcore/data/ef-rp/intro/samples/cu50/Pages/Courses/IndexSelectModel.cshtml.cs	19-33	OnGetAsync method

📝 Preliminary Change Assessment

The following are initial observations for the documentation team to evaluate—not final decisions.

Potential Documentation Updates

File: aspnetcore/data/ef-rp/read-related-data.md
Location: Lines 132-140 (the "Loading related data with Select" section, aspnetcore-5.0+ moniker)
Type: Expanded explanation / Note block

Current content (lines 132-140):

### Loading related data with Select

The `OnGetAsync` method loads related data with the `Include` method. The `Select` method is an alternative that loads only the related data needed. For single items, like the `Department.Name` it uses a SQL INNER JOIN. For collections, it uses another database access, but so does the `Include` operator on collections.

The following code loads related data with the `Select` method:

[!code-csharp[](intro/samples/cu50/Pages/Courses/IndexSelectModel.cshtml.cs?name=snippet_RevisedIndexMethod&highlight=6)]

The preceding code doesn't return any entity types, therefore no tracking is done.

Suggested direction:

### Loading related data with Select

The `OnGetAsync` method loads related data with the `Include` method. The `Select` method is an alternative that loads only the related data needed. For single items, like the `Department.Name` it uses a SQL INNER JOIN. For collections, it uses another database access, but so does the `Include` operator on collections.

> [!NOTE]
> The `Select` method used here is a LINQ **projection** operator. It transforms each element in the source sequence into a new form—in this case, a `CourseViewModel`. Because the query projects into a non-entity type, EF Core generates a SQL query that retrieves only the columns needed for the projection, and no entity tracking is performed.

The following code loads related data with the `Select` method, projecting each `Course` into a `CourseViewModel`:

[!code-csharp[](intro/samples/cu50/Pages/Courses/IndexSelectModel.cshtml.cs?name=snippet_RevisedIndexMethod&highlight=6)]

The preceding code doesn't return any entity types, therefore no tracking is done.

🎯 Suggested Action Plan

For documentation team review

1. Review file: aspnetcore/data/ef-rp/read-related-data.md

   • Navigate to: Lines 132-140 (aspnetcore-5.0+ moniker)
   • Also: Lines 404-412 (aspnetcore-3.0 moniker)
   • Section: "Loading related data with Select"
   • Consider: Adding a [!NOTE] block explaining that Select is a projection operator that transforms elements into a new form

2. Evaluate scope: Decide whether the anonymous type example suggested by the reporter adds value to this tutorial or would add unnecessary complexity.

⚠️ Review Considerations

• The same section appears in both the >= aspnetcore-5.0 and >= aspnetcore-3.0 < aspnetcore-5.0 moniker ranges — both should be updated consistently
• The reporter's anonymous type example is valid C# but may be out of scope for this tutorial which focuses on Razor Pages patterns using strongly-typed view models
• Consider whether this section should more clearly differentiate projection from loading strategies (eager/explicit/lazy)

🔗 References

• Published article: https://learn.microsoft.com/en-us/aspnet/core/data/ef-rp/read-related-data?view=aspnetcore-10.0
• Source file: https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/data/ef-rp/read-related-data.md
• Code sample: https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/data/ef-rp/intro/samples/cu50/Pages/Courses/IndexSelectModel.cshtml.cs
• LINQ Select documentation: https://learn.microsoft.com/en-us/dotnet/api/system.linq.enumerable.select

[smiller7812]

Yes sir:)

…

________________________________ From: Wade Pickett ***@***.***> Sent: Thursday, May 21, 2026 1:28 PM To: dotnet/AspNetCore.Docs ***@***.***> Cc: Samuel Miller ***@***.***>; Mention ***@***.***> Subject: Re: [dotnet/AspNetCore.Docs] note Select is used to project elements into a sequence (Issue #37178) [https://avatars.githubusercontent.com/u/10985336?s=20&v=4]wadepickett left a comment (dotnet/AspNetCore.Docs#37178)<#37178 (comment)> @smiller7812<https://github.com/smiller7812>, Thanks very much for taking the time to let us know. We will take a look! — Reply to this email directly, view it on GitHub<#37178 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AM4QAHCKD5SVGVNPMFVCUPL4344FVAVCNFSM6AAAAACZHRVNHGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DKMJQHA2DOMRWHA>. Triage notifications on the go with GitHub Mobile for iOS<https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android<https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you were mentioned.Message ID: ***@***.***>