DOI is a mechanism for identifying digital resources, which can identify objects such as videos, reports and books. It has the characteristics of uniqueness, persistence, compatibility, interoperability and dynamic update.
The prefix of DOI is determined by the International Digital Object Identification Number Foundation, and resource publishers specify their own suffixes to distinguish different digital materials. It can be embodied in the form of QR code, barcode, character code, network domain name, etc. It is the "ID card" number in the digital age.