ISO date

Most dates in erplain use the ISO 8601 format YYYY-MM-DDTHH:MM:SS+HH:HH. These have the type Date.
As an example, 1977-04-22T01:00:00-05:00 uses this format.

Date No Hour

However hours aren't always needed in a date, therefore some fields only return the format YYYY-MM-DD.
As an example, 1977-04-22 uses this format. These have the type DateNoHour.