SQLite doesn't honor StringLength

[xyzcliu]

Description

https://learn.microsoft.com/en-us/aspnet/core/tutorials/razor-pages/validation?view=aspnetcore-10.0&tabs=visual-studio#apply-migrations
The output SQL is not what SQLite produces, so I spenta bunch of time trying to figure out why this section wasn't working for me. At the beginning of the tutorial, you suggested using SQLite for development. It's worth noting in the final section that in development mode, SQLite does not support StringLength because it casts string as TEXT not VARCHAR. See this bug dotnet/efcore#3698

Page URL

https://learn.microsoft.com/en-us/aspnet/core/tutorials/razor-pages/?view=aspnetcore-10.0

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/tutorials/razor-pages/index.md

Document ID

3e28328b-9c7a-359b-2f57-319b0bc7eea3

Platform Id

4b94ee47-4be6-a01e-c00e-77f6e53fbf71

Article author

@wadepickett

Metadata

• ID: 66f32b67-7418-7f82-c813-c11650bb39a7
• PlatformId: 4b94ee47-4be6-a01e-c00e-77f6e53fbf71
• Service: aspnet-core
• Sub-service: tutorials

Related Issues

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Associated WorkItem - 626915

[wadepickett]

Hi @xyzcliu, I see we need to make a change here and uppdate. Thanks very much for bringing this to our attention!

[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 does not represent a final decision. A team member will review this analysis before any action is taken.

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This preliminary assessment report was run by: @wadepickett
Date: 2026-08-22
Issue: 37507
Model: GitHub Copilot

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Issue Analysis: SQLite migration output doesn't match the SQL Server schema shown in the Razor Pages validation tutorial

✅ Issue Validation

Status: Valid and actionable

📋 Issue Summary

In the Razor Pages tutorial, Part 4 ("Work with a database") instructs Visual Studio Code users to use SQLite for local development. However, in Part 8 ("Add validation"), the "Apply migrations" section shows SQL Server output (NVARCHAR(60), NVARCHAR(30), NVARCHAR(5), etc.) in both the migration Up method snippet and the final SQL schema block. A reader who followed the SQLite path sees different generated code because SQLite maps string to TEXT and ignores length/precision constraints ([StringLength] / HasMaxLength). This mismatch causes confusion — the reporter spent significant time trying to reconcile the documented schema with what SQLite actually produces.

This is a genuine, documented behavior of the EF Core SQLite provider (SQLite has a minimal type system; string → TEXT, length is not applied to the schema). The referenced dotnet/efcore#3698 ("SQLite Migrations: Preserve column max length", closed as not planned) confirms that SQLite effectively ignores length/precision/scale values. This is a documentation clarity gap, not a product bug — the fix is to note the SQLite behavior so SQLite users aren't confused. Importantly, [StringLength] continues to be enforced by ASP.NET Core model validation (client- and server-side); only the generated database column definition differs.

📁 Potentially Affected Files

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

File	Path	Lines	Section
Validation article (main)	aspnetcore/tutorials/razor-pages/validation.md	194-260	"Apply migrations"
Validation article (Up method snippet reference)	aspnetcore/tutorials/razor-pages/validation.md	244-246	"Examine the Up method"
Validation article (schema output)	aspnetcore/tutorials/razor-pages/validation.md	248-260	Updated Movie table schema
Migration snippet (SQL Server–specific, shown to both tabs)	.../Migrations/20230606012811_New_DataAnnotations.cs	14-39	Up method (nvarchar(60/5/30))
Model (source of the length attributes)	.../Models/MovieDateRatingDA.cs	14-38	[StringLength] on Title/Genre/Rating
SQL / database article (where SQLite is introduced)	aspnetcore/tutorials/razor-pages/sql.md	68-96	"SQLite" (VS Code tab)

📝 Preliminary Change Assessment

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

Potential documentation Updates

File: aspnetcore/tutorials/razor-pages/validation.md
Location: Lines 248-260 (the "updated Movie table" schema block, immediately after the Up method snippet), within the "Apply migrations" section
Type: Note block

Current content (lines 248-260):

The updated `Movie` table has the following schema:

​```sql
CREATE TABLE [dbo].[Movie] (
    [ID]          INT             IDENTITY (1, 1) NOT NULL,
    [Title]       NVARCHAR (60)   NOT NULL,
    [ReleaseDate] DATETIME2 (7)   NOT NULL,
    [Genre]       NVARCHAR (30)   NOT NULL,
    [Price]       DECIMAL (18, 2) NOT NULL,
    [Rating]      NVARCHAR (5)    NOT NULL,
    CONSTRAINT [PK_Movie] PRIMARY KEY CLUSTERED ([ID] ASC)
);
​```

Suggested direction: Add a [!NOTE] after the schema block clarifying that the SQL Server output is shown, and that SQLite users will see different output (in both the Up method and the created table) because SQLite maps strings to TEXT and ignores length constraints.

> [!NOTE]
> The preceding `Up` method and schema show the **SQL Server** output. If you're following the tutorial with **SQLite** (the option used in the Visual Studio Code path), the generated migration and table differ. SQLite has a minimal type system that maps `string` properties to `TEXT` and **doesn't apply `[StringLength]`/maximum-length constraints** to the schema, so columns such as `Title`, `Genre`, and `Rating` are created as `TEXT` without a length. The length values are still enforced by ASP.NET Core model validation, just not by the database schema. For more information, see [SQLite EF Core Database Provider Limitations](/ef/core/providers/sqlite/limitations).

🎯 Suggested Action Plan

For documentation team review

1. Review file: aspnetcore/tutorials/razor-pages/validation.md

   • Navigate to: Lines 248-260
   • Section: "Apply migrations"
   • Consider: A [!NOTE] block after the schema explaining that SQLite output differs — in both the Up method snippet (lines 244-246) and the final SQL block — with string → TEXT and length not applied, and that [StringLength] is still enforced by ASP.NET Core model validation.

2. Review file: aspnetcore/tutorials/razor-pages/sql.md

   • Navigate to: Lines 80-94
   • Section: "SQLite" (VS Code tab)
   • Consider: This section already links to SQLite EF Core Provider Limitations; optionally cross-reference forward to the validation/migrations step so the length-constraint behavior is expected.

⚠️ Review Considerations

• Applies to the >= aspnetcore-10.0 moniker content shown here; consider whether the same note is needed in the versioned INCLUDE files (validation9.md, validation8.md, validation7.md, validation6.md, validation3-5.md) referenced at the bottom of validation.md (lines 281-289).
• The migration Up snippet (New_DataAnnotations.cs, lines 14-39) is rendered to both the Visual Studio and Visual Studio Code tabs (the [!code-csharp] include at line 246 is not tab-split), so a SQLite reader sees SQL Server nvarchar(...) code that their tooling would not generate. The note should reference both the Up method and the SQL block.
• Since the tutorial deliberately shows SQL Server (NVARCHAR/dbo) output while the VS Code tab uses SQLite, a note is the least intrusive fix; fully re-authoring both the Up snippet and the schema output for both providers is a larger change.
• Precision on enforcement: [StringLength] is enforced by ASP.NET Core DataAnnotations model validation (client/server), not by EF Core SaveChanges (EF Core does not run DataAnnotations validation on save by default) and not by the SQLite database. Wording should avoid implying DB-level or automatic SaveChanges enforcement.

🔗 References

• Published article: https://learn.microsoft.com/en-us/aspnet/core/tutorials/razor-pages/validation?view=aspnetcore-10.0&tabs=visual-studio#apply-migrations
• Related issue: dotnet/efcore#3698 — "SQLite Migrations: Preserve column max length" (closed, not planned)
• Microsoft Learn docs: SQLite EF Core Database Provider Limitations