Add "Apply migrations" section to MVC validation tutorial

[Copilot]

The ASP.NET Core MVC validation tutorial (Part 9) was missing guidance on running an EF Core migration after adding validation attributes that affect the database schema — leaving the model and DB schema out of sync. The Razor Pages equivalent tutorial already had this section.

Changes

• validation.md (≥ aspnetcore-10.0) and versioned includes for 6.0–9.0 (validation6.md–validation9.md): Added ## Apply migrations section after "Using DataType Attributes" and before "Additional resources"

The new section explains that [Required] → NOT NULL and [StringLength(60)] → nvarchar(60), and provides tabbed migration commands:

• Visual Studio: incremental migration via PMC

  Add-Migration New_DataAnnotations
  Update-Database

• Visual Studio Code: delete-and-recreate (required due to SQLite ALTER TABLE limitations, consistent with Part 8)

  dotnet ef migrations add InitialCreate
  dotnet ef database update
  

• Updated ms.date and added ai-usage: ai-assisted to validation.md frontmatter

Original prompt

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This section details on the original issue you should resolve

<issue_title>For consistency: add-migration after applying validation rules</issue_title>
<issue_description>It's worth mentioning that some validation rules must be applied to the DB schema for consistency by adding a new migration. e.g. add-migration AddingNewRules

Mainly, the following two attributes affect the schema:
1- [Required] will alter the relevant column and make it not null
2- [StringLength(60)] will alter the type of the column and make it nvarchar(60)

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Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: 443a7c53-cc16-7ed5-5950-46a6f195f19c
• Version Independent ID: 12fe9329-2cef-4056-4986-18ed7ae5c397
• Content: Add validation to an ASP.NET Core MVC app
• Content Source: aspnetcore/tutorials/first-mvc-app/validation.md
• Product: aspnet-core
• GitHub Login: @Rick-Anderson
• Microsoft Alias: riande</issue_description>

Comments on the Issue (you are @copilot in this section)

@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 or answer to your question—it's an internal triage tool that identifies potentially relevant docs, code samples, and versions to look into. A team member will review this issue and respond. Thank you for your contribution!

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This preliminary assessment report was run by: @wadepickett
Date: 2026-02-27
Issue: 10429
Model: GitHub Copilot

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Issue Analysis: Add migration step after applying validation rules for database schema consistency

✅ Issue Validation

Status: Valid and actionable

📋 Issue Summary

The issue requests that the Part 9 "Add validation" tutorial mention running an EF Core migration after adding validation attributes that affect the database schema—specifically [Required] (makes columns NOT NULL) and [StringLength(60)] (changes columns to nvarchar(60)).

After a careful walkthrough of all 10 parts of the tutorial series, the issue's core observation is confirmed:

Tutorial Schema Evolution (verified)

Tutorial Part	Model Change	Migration Created?	DB Schema After
Part 4 (adding-model)	Initial Movie class created (no validation attrs)	✅ InitialCreate	Title nvarchar(max) NULL, Genre nvarchar(max) NULL
Part 6 (controller-methods-views)	Adds [Display], [DataType], [Column(TypeName)]	❌ No migration	Same — [Display]/[DataType] don't affect schema; [Column] already matched
Part 8 (new-field)	Adds Rating property	✅ Add-Migration Rating	Adds Rating nvarchar(max) NULL column
Part 9 (validation)	Adds [Required], [StringLength(60)], [StringLength(30)], [StringLength(5)], [RegularExpression], [Range]	❌ No migration	Schema unchanged — columns remain nvarchar(max), NULL despite model constraints

Result: After Part 9, the application enforces validation at the client and server level, but the database schema does not enforce NOT NULL or length constraints. This is the exact gap the issue author identified.

Why the tutorial "works" without the migration

Part 9 begins with a "Delete the previously edited data" section (Line 30-33) that instructs users to delete all movies so seed data can repopulate. This prevents runtime exceptions from existing NULL data conflicting with [Required], but it does not update the database schema itself. The app-level validation prevents bad data from reaching the database, so the tutorial "works" — but the schema and model are out of sync.

📁 Potentially Affected Files

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

File	Path	Lines	Section
Main article (10.0)	aspnetcore/tutorials/first-mvc-app/validation.md	57-62	After validation attribute descriptions, before "Validation Error UI"
Versioned include (9.0)	aspnetcore/tutorials/first-mvc-app/validation/includes/validation9.md	—	Equivalent section
Versioned ...

• Fixes For consistency: add-migration after applying validation rules #10429

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