DNS names have a hierarchical structure, such as sales.general-widget.com. or cs.uni.edu One way to maintain the DNS

Question:

DNS names have a hierarchical structure, such as sales.general-widget.com. or cs.uni.edu One way to maintain the DNS database would be as one centralized database, but that is not done because it would get too many requests/sec. Propose a way that the DNS database could be maintained in practice.