UPDM — Section: 8.6.33.6 Constraints

[1] [1] If a Needline exists between two OperationalNodes, then there must exist a SystemsNode that hosts each of the OperationalNodes and a SystemInterface must exist between them.
This OCL only checks for the existence of a SystemInterface it says nothing about the Needline and the Systems nodes.
The systemsNodes would have to have Systems that are connected by the System Interface, and the SystemInterfaceImplementsNeedline association to associate the Needline and the SystemInterface. The constraint as described in [1] would have to be on SystemsNode, not on an individual system. This constraint may be OK for :"There must be at least one SystemInterface defined on a System".
self.getAllAttributes()>asOrderedSet()>
select(association->notEmpty()).association->any
(getAppliedStereotype('UPDM::SystemInterface')> notEmpty())>notEmpty()