4.3.9 Period of Time

Basic Definition | Formal Definition | Description| Example

Basic Definition

Value Name
PERIOD
Purpose
This value type is used to identify values that contain a precise period of time.

Formal Definition

The data type is defined by the following
notation:

  period     = period-explicit / period-start

  period-explicit = date-time "/" date-time
  ; [ISO 8601] complete representation basic format for a period of
  ; time consisting of a start and end. The start MUST be before the
  ; end.

  period-start = date-time "/" dur-value
  ; [ISO 8601] complete representation basic format for a period of
  ; time consisting of a start and positive duration of time.

Description

If the property permits, multiple "period" values are specified by a COMMA character (US-ASCII decimal 44) separated list of values. There are two forms of a period of time. First, a period of time is identified by its start and its end. This format is expressed as the [ISO 8601] complete representation, basic format for "DATE-TIME" start of the period, followed by a SOLIDUS character (US-ASCII decimal 47), followed by the "DATE-TIME" of the end of the period. The start of the period MUST be before the end of the period. Second, a period of time can also be defined by a start and a positive duration of time. The format is expressed as the [ISO 8601] complete representation, basic format for the "DATE-TIME" start of the period, followed by a SOLIDUS character (US-ASCII decimal 47), followed by the [ISO 8601] basic format for "DURATION" of the period.

Example

The period starting at 18:00:00 UTC, on January 1, 1997 and
ending at 07:00:00 UTC on January 2, 1997 would be:

  19970101T180000Z/19970102T070000Z

The period start at 18:00:00 on January 1, 1997 and lasting 5 hours
and 30 minutes would be:

  19970101T180000Z/PT5H30M

No additional content value encoding (i.e., BACKSLASH character
encoding) is defined for this value type.