Encoding a GML property inline vs. by-reference shall not imply anything about the "ownership" of the contained or referenced GML Object, i.e. the encoding style shall not imply any "deep-copy" or "deep-delete" semantics. To express ownership over the contained or referenced GML Object, the gml:OwnershipAttributeGroup attribute group may be added to object-valued property elements. If the attribute group is not part of the content model of such a property element, then the value may not be "owned".When the value of the owns attribute is "true", the existence of inline or referenced object(s) depends upon the existence of the parent object.
<attributeGroup name="OwnershipAttributeGroup"><annotation><documentation>Encoding a GML property inline vs. by-reference shall not imply anything about the "ownership" of the contained or referenced GML Object, i.e. the encoding style shall not imply any "deep-copy" or "deep-delete" semantics. To express ownership over the contained or referenced GML Object, the gml:OwnershipAttributeGroup attribute group may be added to object-valued property elements. If the attribute group is not part of the content model of such a property element, then the value may not be "owned". When the value of the owns attribute is "true", the existence of inline or referenced object(s) depends upon the existence of the parent object.</documentation></annotation><attribute name="owns" type="boolean" default="false"/></attributeGroup>