diff --git a/entity-framework/core/what-is-new/ef-core-6.0/breaking-changes.md b/entity-framework/core/what-is-new/ef-core-6.0/breaking-changes.md index 4b3bf78896..8171faf801 100644 --- a/entity-framework/core/what-is-new/ef-core-6.0/breaking-changes.md +++ b/entity-framework/core/what-is-new/ef-core-6.0/breaking-changes.md @@ -17,6 +17,7 @@ The following API and behavior changes have the potential to break existing appl | [Cleaned up mapping between DeleteBehavior and ON DELETE values](#on-delete) | Low | | [Removed last ORDER BY when joining for collections](#last-order-by) | Low | | [DbSet no longer implements IAsyncEnumerable](#dbset-iasyncenumerable) | Low | +| [New snapshot model initialization procedure](#snapshot-initialization) | Low | ## Low-impact changes @@ -128,3 +129,45 @@ The vast majority of `DbSet` usages will continue to work as-is, since they comp #### Mitigations If you need to refer to a as an , call to explicitly cast it. + + + +### New snapshot model initialization procedure + +[Tracking Issue #22031](https://github.com/dotnet/efcore/issues/22031) + +#### Old behavior + +In EF Core 5, specific conventions needed to be invoked before the snapshot model was ready to be used. + +#### New behavior + + was introduced to hide some of the required steps, and a run-time model was introduced that doesn't have all the migrations metadata, so the design-time model should be used for model diffing. + +#### Why + + abstracts away the model finalization steps, so these can now be changed without further breaking changes for the users. + +The optimized run-time model was introduced to improve run-time performance. It has several optimizations, one of which is removing metadata that is not used at run-time. + +#### Mitigations + +The following snippet illustrates how to check whether the current model is different from the snapshot model: + +```csharp +var snapshotModel = migrationsAssembly.ModelSnapshot?.Model; + +if (snapshotModel is IMutableModel mutableModel) +{ + snapshotModel = mutableModel.FinalizeModel(); +} + +if (snapshotModel != null) +{ + snapshotModel = context.GetService().Initialize(snapshotModel); +} + +var hasDifferences = context.GetService().HasDifferences( + snapshotModel?.GetRelationalModel(), + context.GetService().Model.GetRelationalModel()); +```