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:

   // 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.

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