Extension References

Extension References can be described are reverse Composition References. They create a parent-child relationship where the parent has no knowledge of the child. This is used to attach elements with new ElementClasses to Models of pre-existing metamodels.

Extensions:

• Are one-directional, but they point from the child ElementClass to the parent.
• Create a hierarchy where the target (parent) contains the owner (child).

model/references/QuerySearch_dataElement.xml

<reference name="dataElement">
  <associationType name="association"/>
  <owner name="QuerySearch" ontology="querysearch"/>
  <target name="DataElement" ontology="elements"/>
  <cardinality>
    <minimum>0</minimum>
    <maximum>1</maximum>
  </cardinality>
</reference>

See Model Extensions to learn how Extension References are used.