oracle中几个name

oracle_sid, sid, oracle system identifier.mainly a env variable.

db_name, the name of the database.is the name which is in:
create database db_name(this one.)

service_name, the name which the database regiester to the listener. and listener resolves this service_name from clients.

instance name = sid.

global_name: = sid+db_domain. used in distributed database env.
but after u issue alter database rename global_name then they are not the same.