Hi,

Using the new IBM.EntityFrameworkCore 8.0.0.100 package we get an exception thrown when using decimal as key for entity. Caused by IBM.EntityFrameworkCore.Internal.Db2Strings.LogDecimalTypeKey(IDiagnosticsLogger logger). 

Value cannot be null. (Parameter 'format')'

   at System.ThrowHelper.Throw(String paramName)
   at Microsoft.Extensions.Logging.LogValuesFormatter..ctor(String format)
   at Microsoft.Extensions.Logging.LoggerMessage.CreateLogValuesFormatter(String formatString, Int32 expectedNamedParameterCount)
   at Microsoft.Extensions.Logging.LoggerMessage.Define[T1,T2](LogLevel logLevel, EventId eventId, String formatString, LogDefineOptions options)
   at Microsoft.Extensions.Logging.LoggerMessage.Define[T1,T2](LogLevel logLevel, EventId eventId, String formatString)
   at IBM.EntityFrameworkCore.Internal.Db2Strings.<>c.<LogDecimalTypeKey>b__21_1(LogLevel level)
   at Microsoft.EntityFrameworkCore.Diagnostics.EventDefinition`2..ctor(ILoggingOptions loggingOptions, EventId eventId, LogLevel level, String eventIdCode, Func`2 logActionFunc)
   at IBM.EntityFrameworkCore.Internal.Db2Strings.<>c__DisplayClass21_0.<LogDecimalTypeKey>b__0()
   at System.Threading.LazyInitializer.EnsureInitializedCore[T](T& target, Func`1 valueFactory)
   at IBM.EntityFrameworkCore.Internal.Db2Strings.LogDecimalTypeKey(IDiagnosticsLogger logger)
   at IBM.EntityFrameworkCore.Internal.Db2LoggerExtensions.DecimalTypeKeyWarning(IDiagnosticsLogger`1 diagnostics, IProperty property)
   at IBM.EntityFrameworkCore.Infrastructure.Internal.Db2ModelValidator.ValidateDecimalColumns(IModel model, IDiagnosticsLogger`1 logger)
 at IBM.EntityFrameworkCore.Infrastructure.Internal.Db2ModelValidator.Validate(IModel model, IDiagnosticsLogger`1 logger)

In our case we could resolve this temporarily using:

            .HasColumnType("decimal(2, 0)")
          .HasConversion<int>()