That is why MARC has tag and subfield markers, which allow software to understand exactly how to treat each descriptive element. Some do, such as when records for digital objects are merged with a library catalog and loaded into the catalog as with the record for a print book. The State Library of Victoria Multimedia Catalogue has over 120,000 records for digital objects. However, for many purposes, MARC is a poor fit. Of these categories, MARC really only deals well with intellectual metadata.
Structural metadata describes how the item is structured.
In a book, pages follow another. Administrative metadata may include such things as how the digital file was produced and its ownership. All of this potential metadata needs containers. However, most of the metadata described above has no standard container waiting to receive it, as MARC receives the information specified by AACR2. There are, however, some emerging standards that may be to digital libraries what MARC was to print-based libraries.