anchor.diff:      procedure Assign(aValue : TNullableInteger); overload;
       procedure Assign(aValue : TNullableDateTime); overload;
       procedure Assign(aValue : TNullableDouble); overload;
  +    procedure Assign(aValue : TNullableBoolean; const aConvention: TmBooleanParameterConvention); overload;
       procedure Assign(const aFilter : TmFilter); overload;
   
       procedure AsStringList (aList : TStringList);
  
positive.code:     Self.AsFloat:= aValue.Value;
  end;
  
  procedure TmQueryParameter.Assign(const aFilter : TmFilter);
  begin
    if aFilter.DataType = fdtDate then
  
negative.code:   TmDatabaseVendor = (dvUnknown, dvSQLServer);
  
    TmParameterDataType = (ptUnknown, ptDate, ptDateTime, ptInteger, ptFloat, ptString, ptWideString);
  
    TmBooleanParameterConvention = (bpcUseIntegers);
  
  { TmQueryParameter }
  
  