A virtual document is a container for component documents, which are either simple documents of type dm_sysobject
(or a subtype excluding dm_folder
and its subtypes) or virtual documents. Even though its primary purpose is to act as a container, a virtual document object can have content of its own.
Note
Note that it is a recursive definition — the definition of virtual document, in turn, uses the term virtual document. In computer science, recursive definitions facilitate description of tree-like structures. We will see in a moment that virtual documents also have a tree structure.
Note that there is no limit on the depth of the hierarchy — a virtual document can contain another virtual document, which can contain another virtual document, and so on. The containment relationship between a virtual document and its component is known as nesting.
The components in the virtual document hierarchy are ordered, which means that there is a sequence among the direct components...