---
name: dotnet-entity-framework6
version: "1.0.1"
category: "Data, Distributed, and AI"
description: "Maintain or migrate EF6-based applications with realistic guidance on what to keep, what to modernize, and when EF Core is or is not the right next step. Use when working in an EF6 codebase or planning a data layer migration."
compatibility: "Requires EF6 or a transition plan from EF6 to EF Core or modern .NET."
---

# Entity Framework 6

## Trigger On

- working in an EF6 codebase on .NET Framework or modern .NET
- deciding whether to keep EF6, move to modern .NET runtime, or port to EF Core
- reviewing EDMX, code-first, or legacy ASP.NET/WPF/WinForms data access
- planning a data layer migration strategy

## Workflow

1. **Audit current EF6 usage** before planning any migration. Identify which features the codebase depends on:
   ```csharp
   // Common EF6-specific patterns to inventory:
   // - EDMX designer models (check for *.edmx files)
   // - ObjectContext vs DbContext usage
   // - Lazy loading with virtual navigation properties
   // - Database.SqlQuery<T>() for raw SQL
   // - Stored procedure mappings in model
   // - Spatial types (DbGeography, DbGeometry)
   ```
2. **Decide runtime vs ORM migration separately:**

   | Path | When to use |
   |------|-------------|
   | Keep EF6 on .NET Framework | Legacy app with no runtime pressure |
   | EF6 on modern .NET | Runtime upgrade needed, ORM migration too risky |
   | EF6 → EF Core | Clean data layer, no EDMX, minimal stored-procedure mapping |

3. **For maintenance work** — keep EF6 stable:
   - use repository + unit of work patterns to isolate data access (see references/patterns.md)
   - prefer `DbContext` over `ObjectContext` for new code
   - use `AsNoTracking()` for read-only queries
   - configure concurrency tokens with `[ConcurrencyCheck]` or `IsRowVersion()`
4. **For migration work** — validate each slice:
   - map EF6 features to EF Core equivalents (see references/migration.md)
   - migrate one bounded context at a time, not the entire data layer
   - run integration tests against the real database provider, not InMemory
   - verify: `dotnet ef migrations add` succeeds, queries produce equivalent results, lazy loading behavior matches expectations
5. **Do not promise EF Core features to EF6 codebases** — EF6 is stable and supported but not on the innovation path. Keep expectations realistic.

```mermaid
flowchart LR
  A["Audit EF6 usage"] --> B{"EDMX or complex mappings?"}
  B -->|Yes| C["High migration cost — consider keeping EF6"]
  B -->|No| D["Evaluate EF Core migration"]
  D --> E["Migrate one context at a time"]
  E --> F["Integration test against real DB"]
  C --> G["Modernize runtime only"]
  F --> H["Validate query equivalence"]
  G --> H
```

## Deliver

- realistic EF6 maintenance or migration guidance based on actual codebase audit
- clear separation between runtime upgrade and ORM upgrade work
- bounded migration slices with concrete validation checkpoints
- reduced risk for legacy data access changes

## Validate

- EF6 feature inventory is complete before migration planning starts
- migration assumptions are backed by real feature usage, not guesses
- EF6-only features (EDMX, spatial types, ObjectContext patterns) are identified early
- integration tests run against the real database provider, not mocks or InMemory
- the proposed path avoids unnecessary churn in stable data access code

## References

- references/migration.md - decision framework, migration approaches, EF6-to-EF Core feature mapping, and common pitfalls
- references/patterns.md - repository and unit of work patterns, query optimization, concurrency handling, auditing, and testing strategies for EF6 codebases
