A DOI name is a global unique identifier of an entity (called the referent). The referent can be any digital, physical or abstract entity, and it can be defined on any granularity level of an entity depending on the requirements of the Registration Agency (RA); and a DOI name may identify a specific edition of a novel, a novel chapter, a small piece of musical recording, etc. Referents can be intellectual property where examples would include inventions, literary and artistic works, ideas, symbols, names, images, designs, etc.
A DOI name can be resolved, through a Handle System service, to a set of elements, called the DOI record, as illustrated below. The DOI record usually contains a web address (or URL for Unified Resource Locator) representing an instance of the referent, and may contain services such as email, and one or more items of data about the referent (metadata).
The figure below shows an example where the referent is the specific edition of a novel and the author of the novel. A referent could also be a chapter of the novel, etc.
The DOI name is persistent over time. Its persistence is provided by the independence of the identifier name from the element values, in particular from the entity localization or ownership. These elements can change over time: through the DOI name resolution, users will always get the up-to-date element values (This requires that the DOI record data be regularly maintained.).
NOTE Each element of the DOI record is assigned an explicit type (for example, "URL" (web address) or "email"). Predefined types exist in the Handle System and new types can be added at any time by RAs, making the DOI resolution system extremely flexible and responsive to new requirements.