Database First Approach with EF Core (Scaffold)

Introduction

Not every ShopNest integration starts greenfield. Database First scaffolds entities from an existing HR database — common when migrating legacy systems at TCS/Wipro-style maintenance projects.

After this article you will

• Run dotnet ef dbcontext scaffold with options
• Extend scaffolded models with partial classes
• Refresh after DBA schema changes
• Map stored procedures and database views
• Mix Code First for new modules on same DB

Prerequisites

• Article 20 — EF Core Performance Optimization
• ShopNest DbContext with Products/Orders from Articles 13–15
• SQL Server or LocalDB configured

Concept deep-dive

dotnet ef dbcontext scaffold   "Server=.;Database=LegacyHR;Trusted_Connection=True;"   Microsoft.EntityFrameworkCore.SqlServer   --output-dir Models/Scaffolded   --context-dir Data   --context LegacyHrContext   --force   --no-onconfiguring

Partial classes: never edit scaffolded files — add Employee.Partial.cs with computed properties.

// Keyless entity for DB view
modelBuilder.Entity<EmployeeSummaryView>(b =>
{
    b.HasNoKey();
    b.ToView("vw_EmployeeSummary");
});

// Stored procedure
var results = await _db.EmployeeBonuses
    .FromSqlRaw("EXEC hr.GetBonuses @Year = {0}", 2025)
    .ToListAsync();

Hands-on — ShopNest Legacy HR System Migration

1. Scaffold from sample LegacyHR database (or LocalDB script).
2. Partial class adds FullName computed property.
3. Map reporting view as keyless entity for read-only dashboard.
4. Document re-scaffold workflow for team when DBA adds columns.

Common errors & best practices

• Editing generated files — overwritten on re-scaffold; use partials.
• Scaffolding entire server with 200 tables — scaffold specific tables with --table flags.

Interview questions

Q: When Database First?
A: Legacy DB, no ownership of schema, brownfield migration.

Q: Code First vs Database First?
A: Code First — dev owns schema. Database First — DBA owns schema, app adapts.

Summary

• Scaffold-DbContext reverse-engineers existing SQL Server
• Partial classes extend without losing regeneration
• Views and sprocs map to keyless entities / FromSqlRaw
• Common in legacy HR migration scenarios

Previous: EF Core Performance Optimization
Next: EF Core with SQL Server — Advanced Features

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