A complex data type instance may be referenced in a number of collections. Each independent object instance belongs, however, to exactly one owning collection, which is considered as the owner of its instances. Usually, global collections (root extents) own collections by default. Also reference properties usually define local owning collections. Relationships may define owning or not owning collections.
When adding an instance to an owning collection, the instance will be created. Instances in an owning collection are dependent instances.