Cardinality defines how many times an element must/may appear in a HL7 message. Represented as minimum and maximum instance counts, e.g., 0-to-n or 1-to-1.
Also seeWhat is Cardinality in HL7?
Field or Segment
Rule
Cardinality
Patient address field (PID-11)
optional and repeating
0 to n
Patient primary language field (PID-15)
optional and non-repeating
0 to 1
Patient class field (PV1-2)
required and non-repeating
1 to 1
The Patient Identification (PID) segment in the Patient Admission message (ADT-A01)
