An operating method for a dynamic random access memory (DRAM) obtains a plurality of first sub-commands of a first activate command via a command bus, and obtaining a plurality of first address information regarding a plurality of first portions of a first row address of a specific bank via an address bus. Each of the first sub-commands corresponds to an individual first portion of the first row address of the specific bank. The method further combines the first portions of the first row address of the specific bank in response to a specific sub-command of the first sub-commands, so as to obtain a first complete row address; and obtains an access command via the command bus.