Periodic intervals in ISO 21090 are the key way in implementing repeating events. PIVL is constrained to apply only to time, there is no other repeating dimension allowed. There is no periodic event equivalent and any periodic events are implemented as a periodic interval with zero duration for that interval using PIVL. The PIVL.phase.low.value attribute defines a known starting point of a repeating duration as a TS, the PIVL.phase.any.value defines the mid point of a range of possible starting points. Within the PIVL data type it is possible to under specify a periodic interval such that it has no set start date, for example, using underspecification of the IVL data type. It does not appear possible to have an uncertain range of dates as the start point. This is implemented as described in ISO 21090.

Specializes

QSET

Attributes

Name	Data type	Occurs	Description
alignment	CalendarCycle	0..1	This is implemented as described in ISO 21090.
count	INT.Pos	1..1	This is implemented as described in ISO 21090.
frequency	RTO	1..1	This is implemented as described in ISO 21090.
isFlexible	Boolean	1..1	This is implemented as described in ISO 21090.
period	PQ	0..1	This is implemented as described in ISO 21090.
phase	IVL_TS	0..1	This is implemented as described in ISO 21090.

Constraints

Type	Name	Specification
no updateMode or History on PIVL attributes	Invariant	inv: noUpdateOrHistory(phase) and noUpdateOrHistory(period)
period or frequency	Invariant	inv: isNotNull implies (period.isNotNull xor frequency.isNotNull)