Can you change the Scaffolding mappings in EF Core?

Is there an example of that somewhere? Is that something I can do so that it's generated correctly when I scaffold it via Scaffold-DBScaffold-DbContext? That's the part I'm having an issue with.

Thanks Alex. :)

I don't see how that solves the problem though? Scaffold-DbContext generated a byte. When I run it again to pick up new database structure changes, it's going to recreate it as a byte.

That's the problem I'm having. A NUMBER(4,0) column comes out as a byte, and as soon as it reads a row with a value like 1234, it fails. I can change the generated classes after the fact, but those changes get wiped out if I run Scaffold-DbContext to recreate from the database again. In the EF6 version, the configuration mapping changes are picked up during this and it would create it as a short instead, which works.

Sorry, but I'm really not understanding what I'd do with the fluent API that would help solve that problem.

Hi Alex. So I tried that, and now saving with the column that has values incompatible with byte gives me the exception below. It doesn't actually matter what's in the column (including null), it simply doesn't work properly. Running it as a byte also isn't an option, because as a NUMBER(4,0), it easily has values that overflow byte.

It's defined in EF as follows:

    public short? PlaceCd { get; set; }

      modelBuilder.Entity<TempAddress>(entity =>

      {

entity.HasIndex(e => e.PlaceCd)

          .HasName("XIF5TEMP_ADDRESS");

entity.Property(e => e.PlaceCd).HasColumnName("PLACE_CD");

}

I can't be sure this is the one that's causing the error as the error doesn't specify which column is the problem, but this is the one that overflows if I use the default mappings.

System.Reflection.TargetInvocationException

 HResult=0x80131604

 Message=Exception has been thrown by the target of an invocation.

 Source=System.Private.CoreLib

 StackTrace:

  at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)

  at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)

  at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)

  at Microsoft.EntityFrameworkCore.Update.Internal.KeyValueIndexFactorySource.Create(IKey key)

  at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)

  at Microsoft.EntityFrameworkCore.Update.Internal.KeyValueIndexFactorySource.GetKeyValueIndexFactory(IKey key)

  at Microsoft.EntityFrameworkCore.Update.Internal.CommandBatchPreparer.AddForeignKeyEdges(Multigraph`2 commandGraph, Dictionary`2 predecessorsMap)

  at Microsoft.EntityFrameworkCore.Update.Internal.CommandBatchPreparer.TopologicalSort(IEnumerable`1 commands)

  at Microsoft.EntityFrameworkCore.Update.Internal.CommandBatchPreparer.<BatchCommands>d__11.MoveNext()

  at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(IEnumerable`1 commandBatches, IRelationalConnection connection)

  at Microsoft.EntityFrameworkCore.Storage.RelationalDatabase.SaveChanges(IList`1 entries)

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IList`1 entriesToSave)

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(DbContext _, Boolean acceptAllChangesOnSuccess)

  at Oracle.EntityFrameworkCore.Storage.Internal.OracleExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)

  at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)

  at Microsoft.EntityFrameworkCore.DbContext.SaveChanges()

  at GNB.ELG.WellVoucher.Website.External.Controllers.VoucherController.Create(VoucherEditVm vm) in C:\workarea\GWIMS\Dev\GNB.ELG.WellVoucher\GNB.ELG.WellVoucher.Website.External\Controllers\VoucherController.cs:line 108

  at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)

  at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)

  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()

  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)

  at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()

Inner Exception 1:

InvalidCastException: Unable to cast object of type 'System.Func`3[System.Byte,System.Byte,System.Boolean]' to type 'System.Func`3[System.Int16,System.Int16,System.Boolean]'.

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.SimplePrincipalKeyValueFactory`1.NoNullsCustomEqualityComparer..ctor(ValueComparer comparer)

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.SimplePrincipalKeyValueFactory`1..ctor(IProperty property)

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.KeyValueFactoryFactory.CreateSimpleFactory[TKey](IKey key)

  at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.KeyValueFactoryFactory.Create[TKey](IKey key)

  at Microsoft.EntityFrameworkCore.Metadata.Internal.Key.<>c__19`1.<GetPrincipalKeyValueFactory>b__19_0(Key k)

  at Microsoft.EntityFrameworkCore.Internal.NonCapturingLazyInitializer.EnsureInitialized[TParam,TValue](TValue& target, TParam param, Func`2 valueFactory)

  at Microsoft.EntityFrameworkCore.Metadata.Internal.Key.GetPrincipalKeyValueFactory[TKey]()

  at Microsoft.EntityFrameworkCore.Metadata.Internal.KeyExtensions.GetPrincipalKeyValueFactory[TKey](IKey key)

  at Microsoft.EntityFrameworkCore.Update.Internal.KeyValueIndexFactorySource.CreateFactory[TKey](IKey key)