Start Debugging

Tag: ef-core

47 posts · Page 2 of 5

2026-06-26 errors csharp dotnet

Fix: FOREIGN KEY constraint failed when deleting an entity in EF Core 11

EF Core throws FOREIGN KEY constraint failed because the parent still has dependents the database refuses to orphan. Load the children, make the relationship optional, or configure OnDelete.

2026-06-26 errors csharp dotnet

Fix: No service for type 'Microsoft.EntityFrameworkCore.DbContextOptions' has been registered

EF Core throws this when AddDbContext never ran, ran after Build, or your context's constructor takes the wrong DbContextOptions. Register before Build and use DbContextOptions<YourContext>.

2026-06-25 errors csharp dotnet

Fix: The seed entity for entity type 'X' cannot be added because a non-zero value is required for property 'Id'

HasData seeds an entity with a store-generated key but no explicit value. Give every seed row a stable non-zero Id, or switch to UseSeeding for generated keys.

2026-06-23 how-to ef-core ef-core-11

How to do keyset (cursor) pagination in EF Core 11

Replace Skip/Take with a WHERE clause that seeks past the last row you saw. Order by a fully unique key, carry the last row's values as a cursor, and EF Core 11 turns the next page into an index seek instead of an OFFSET scan.

2026-06-23 how-to ef-core ef-core-11

How to map and query JSON columns in EF Core 11

Map a nested type to a single JSON column with ComplexProperty(...).ToJson(), let EF Core 11 store it in the native SQL Server 2025 json type, then query into it with LINQ that translates to JSON_VALUE, JSON_CONTAINS, and JSON_PATH_EXISTS.

2026-06-15 comparison ef-core ef-core-11

AsNoTracking vs AsNoTrackingWithIdentityResolution in EF Core 11: which should you use?

Use AsNoTracking for read-only queries by default. Reach for AsNoTrackingWithIdentityResolution only when the result graph contains the same entity more than once and your code depends on getting a single shared instance back.

2026-06-14 dotnet dotnet-11 ef-core

EF Core 11's New EF1004 Analyzer Catches a Silent Async Mistake

EF Core 11 Preview 5 ships the EF1004 analyzer. It flags ToAsyncEnumerable() on an IQueryable so you do not accidentally enumerate a database query synchronously inside an await foreach.

2026-06-12 errors csharp dotnet

Fix: The entity type 'X' requires a primary key to be defined in EF Core 11

EF Core can't find a key for your type. Either name a property Id or {Type}Id, add [Key], call HasKey, or - if it is a view or raw SQL result - call HasNoKey.

2026-06-10 errors csharp dotnet

Fix: The configured execution strategy 'SqlServerRetryingExecutionStrategy' does not support user-initiated transactions

EnableRetryOnFailure conflicts with BeginTransaction. Wrap the whole transaction in db.Database.CreateExecutionStrategy().ExecuteAsync(...) so it retries as one unit.

2026-06-04 comparison ef-core ef-core-11

EF Core ExecuteUpdate vs loading entities and SaveChanges: which should you use?

A decision guide and real benchmark for EF Core 11: use ExecuteUpdate for set-based writes by a predicate, and the load-then-SaveChanges path only when you need the change tracker, interceptors, or a complex object graph.