Fix: Your startup project doesn't reference Microsoft.EntityFrameworkCore.Design
Add Microsoft.EntityFrameworkCore.Design to the startup project that dotnet ef builds, not the project holding your DbContext, and pass -s in layered solutions.
Tag: ef-core
47 posts · Page 1 of 5
Fix: "The model for context 'X' has pending changes" in EF Core 11
EF Core throws PendingModelChangesWarning when your model no longer matches the last migration snapshot. Add the migration, or fix the false positive behind it.
How to apply EF Core 11 migrations in production with dotnet ef migrations bundle
A complete guide to deploying EF Core 11 schema changes with migration bundles: building efbundle in CI, the appsettings.json trap with named connection strings, self-contained bundles and the Alpine musl RID, migration locking since EF Core 9, rolling back with a target migration, and why per-migration transactions do not save you on MySQL.
Complex types vs owned entities in EF Core 11: which should you pick?
On EF Core 11, default to complex types for value objects and drop to owned entities only when you need a separate table or a collection mapped to its own rows.
TPH vs TPT vs TPC inheritance mapping in EF Core 11: which should you pick?
On EF Core 11, default to TPH for almost every hierarchy, reach for TPC only when you mostly query one leaf type and a benchmark proves it wins, and use TPT only when an external constraint forces you to.
Fix: System.InvalidOperationException: Sequence contains no elements
This exception means you called .First() or .Single() on an empty sequence. Use FirstOrDefault/SingleOrDefault and null-check, or guard the query, or fix why the source is empty.
How to log the SQL that EF Core 11 generates
See the exact SQL Entity Framework Core 11 sends to your database, with parameter values, using LogTo, Microsoft.Extensions.Logging, and ToQueryString.
Fix: "The property could not be mapped, because it is not a supported primitive type or a valid entity type" in EF Core 11
EF Core hit a property it does not know how to store. Map it as a complex type, convert it with HasConversion, give it a key, or ignore it with [NotMapped].
How to configure table-per-hierarchy (TPH) inheritance mapping in EF Core 11
TPH is EF Core's default inheritance strategy: one table, one discriminator column. Here is how to configure the discriminator, share columns, handle nullable derived properties, and the gotchas on EF Core 11.
How to map a complex type instead of an owned entity in EF Core 11
Owned entities carry a hidden key and reference identity that fights value objects. Here is how to map a value object as a complex type in EF Core 11, when to switch, and the gotchas.