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What are the formal semantics of 'unique' on a cardinality constraint?

Description

The semantics of the 'unique' constraint in ADL / AOM have not been fully defined. The child objects of a container attribute in openEHR can never be literally identical, since at least the name differs. Therefore, 'unique' must refer to a logical uniqueness of values. For complex objects this is probably mostly meaningless, since sibling complex objects in a container will almost always differ in some detail. For leaf objects, or near-leaf objects it could have some meaning. It could potentially be formalised by the introduction of an '=' operation on data objects.

Environment

None

Status

Reporter

Thomas Beale

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Components

Affects versions

AM version 1.4

Priority

Minor