tkEnumeration:
      begin
        if aValue.TypeInfo = TypeInfo(System.Boolean) then
        begin
          aParam.AsBoolean := aValue.AsBoolean;
        end
        else
        begin
          aParam.AsInteger := aValue.AsOrdinal;
        end;
      end;

type

  TThemes = (Light, Dark);

  [MVCNameCase(ncLowerCase)]
  [MVCTable('sample')]
  TSample = class(TMVCActiveRecord)
  strict protected
    [MVCTableField('theme')]
    FTheme: TThemes;
  public
    [MVCEnumSerialization(estEnumName)]
    [MVCSwagJsonSchemaField(stEnumeration, 'theme', 'Theme', True, False, 0, 1)]
    property Theme: TThemes read FTheme write FTheme;
  end;

TSamples = class(TObjectList<TSample>)
public
  class function ReturnItem: TSample;
end;

implementation

class function TSamples.ReturnItem: TSample;
begin
  Result := TModel.GetFirstByWhere<TSample>('', [], [], False);
end;

        else if (aRTTIField.FieldType.TypeKind = tkEnumeration) then
        begin
          TValue(AField.AsInteger).ExtractRawData(PByte(Pointer(AObject)) + aRTTIField.Offset);
        end

procedure MapDataSetFieldToRTTIField(const AField: TField; const aRTTIField: TRttiField;
const AObject: TObject);
...
begin
  ...
  case AField.DataType of
  ...
    ftInteger, ftSmallint, ftShortint, ftByte:
      begin
        ...
        else if (aRTTIField.FieldType.TypeKind = tkEnumeration) then
        begin
          TValue(AField.AsInteger).ExtractRawData(PByte(Pointer(AObject)) + aRTTIField.Offset);
        end
      end
  ...
  end;
end;