Represents a whole or partial calendar date, e.g. a birthday. The time of day and time zone are either specified elsewhere or are not significant. The date is relative to the Proleptic Gregorian Calendar. This can represent:
- A full date, with non-zero year, month and day values
- A month and day value, with a zero year, e.g. an anniversary
- A year on its own, with zero month and day values
- A year and month value, with a zero day, e.g. a credit card expiration date
Related types are
Year of date. Must be from 1 to 9999, or 0 if specifying a date without a year.
Month of year. Must be from 1 to 12, or 0 if specifying a year without a month and day.
Day of month. Must be from 1 to 31 and valid for the year and month, or 0 if specifying a year by itself or a year and month where the day is not significant.