Differences between global database names and Sid

Global Database Name: The full name of a database that uniquely identifies a database with any other database. The format of the global database name is <database_name>. <database_domain>. For example, student. cs. hubu is a typical global database name. The database name section (such as student) is the simple name of the database. The database Domain Section (such as CS. hubu) specifies the region where the database is located. It is usually the same as the network domain in the enterprise. The database name part of the global database name cannot exceed 8 characters, and can only contain letters, numbers, and periods.
Sid (system identifier): identifies a specific routine of an Oracle database. For any database, there must be at least one routine that references the database. Sid can be any name not used by other routines on this computer. Sid is the unique identifier of an Oracle Data Warehouse routine. It can contain up to 8 letters and numbers. Each data warehouse routine corresponds to a Sid and a series of database files. For example, when a database with the SID of XXX is created, the data library routine and its database files (initialize parameter files, control files, redo log files, and data files) will be created at the same time ).