ActiveRecord DateTime, Time Mappings

It appears to not be possible to call to_xml on an ActiveRecord object with various Time, Datetime columns and have it return the following:

<hour>
    <from>18:00:00</from>
    <until>22:00:00</until>
    <created-at>2008-11-05T08:28:17Z</created-at>
    <updated-at>2008-11-05T09:40:18Z</updated-at>
</hour>

Even if :from and :until were declared as time columns. Because of how ActiveRecord mixes and matches DateTime and Time class mappings (over-optimization), ActiveRecord would output the following instead:

<hour>
    <from>2000-01-01T18:00:00Z</from>
    <until>2000-01-01T22:00:00Z</until>
    <created-at>2008-11-05T08:28:17Z</created-at>
    <updated-at>2008-11-05T09:40:18Z</updated-at>
</hour>

In other words, there appears to be no way to differentiate between a time object: "14:00:00", a date object: "2008-12-15" and a datetime object: "2008-12-15 14:00:00".

At the database level, however, these differentiations are in fact honored, times are stored as times, dates as dates, and datetimes as datetimes.

So the pragmatic position is that the data treatment and the presentation treatment are different, and that the data is being misrepresented.

The world might prove to be a better place if :time were mapped to Time, :datetime to DateTime, and :date to Date. Plus dates before 1970 wouldn't give "out of range" exceptions.

The performance implications of this are of course to be considered. But so should the complexity implications. Even if the performance considerations do justify the more-complicated mapping, this should at least be done properly.