Content Based Access Hierarchy

Content based access always stats with an object space, which can be considered as an instance without schema. An object space instance contains a number of collections (extents), which provide access to object type instances. Object type instances may, again, contain collections, which again provide access to further instances.

Thus, the is an alternating access hierarchy between instance and collection access beginning with the object space instance. The root object space instance is available as root object space of the database, when a database had been opened.