1. A computer-implemented method for modifying an entry name in a directory server, comprising: modifying entry mapping information in a directory database, in response to a request to modify at least one entry name, wherein each piece of entry mapping information is used for indicating a correspondence relation between pre-modification entry name information and post-modification entry name information; wherein the entry mapping information is recorded in an entry mapping information table, and each record of the entry mapping information table includes a pre-modification name field and a post-modification name field; asynchronously performing a modifying operation of the entry name in accordance with respective pieces of entry mapping information when a predetermined condition for updating the directory database is met; wherein the predetermined condition for updating includes at least one: asynchronously performing modifying operation of entry names in a specific period of time; and asynchronously performing modifying operation of entry names when a modification workload reaches a predetermined threshold; searching entries of the directory database and the post-modification name field of the entry mapping table in order to determine whether or not there is an entry name that are a same as the entry name after a requested modification; searching, in response to a result that no entry name that is the same as the entry name after the modification that is requested is found, the pre-modification name field of the entry mapping table in order to determine whether or not there is a entry name that is the same as the entry name before the modification that is requested; and adding, in response to the result that no entry name that is the same as the entry name before the requested modification is found, a new mapping record to the entry mapping table, wherein the pre-modification name field of the record records information associated with the entry name before the requested modification, and the post-modification name field records information associated with the entry name after the requested modification.