Database Name, database instance name Sid, Database Service name, Global Database Name

I. Database Name
It is the name of the database you created when installing the Oracle software, or the data you created after installation. It is mainly used to install multiple databases in an Oracle database,
The distinction between them. A database generates an oracle_service in the Windows Service. The database name is used to install the database, create a new database, and create a database control.
File Creation, data structure modification, backup, and database restoration are all required.
 
Query the current data name
Method 1: Select name from V $ database;
Method 2: Show parameter DB
Ii. database instance name [Sid]
The database instance name is the identifier used to contact the operating system, that is, the interaction between the database and the operating system uses the database instance name. The instance name is also written to the parameter file.
. The Database Name and Instance name can be the same or different. In general,
The Database Name and Instance name are one-to-one relationships. However, in the Oracle Parallel Server Architecture (that is, the Oracle Real-time application cluster), the database name and Instance name are one-to-multiple relationships.
(It indicates the identity for communication between each database and the operating system when multiple databases are created in an Oracle database. It has nothing to do with our users !)

Query the name of the current database instance
Method 1: Select instance_name from V $ instance;
Method 2: Show parameter instance

Iii. Database Domain Name
In the distributed database system, different versions of database servers, regardless of whether the operating system is Unix or windows, can be accessed through the database
Link for remote replication. The database domain name is mainly used for replication in the Oracle distributed environment.
Example:
The distributed database of the National Transportation Administration System, where:
Fujian node: FJ. jtyz
Xiamen node in Fujian: XM. fj. jtyz
Jiangxi: jx. jtyz
Shangrao, Jiangxi: Sr. jx. jtyz
This is the database domain name.
The database domain name exists in the parameter file. Its parameter is db_domain.

Query database domain names
Method 1: Select value from V $ parameter where name = 'db _ Domain ';
Method 2: Show parameter domain

Iv. Global Database Name
Global Database Name = database name + database domain name. For example, the Global Database Name of the preceding Fujian node is oradb. fj. jtyz.
V. Database Service name
A new parameter, that is, the Database Service name, is introduced from Oracle9i. The parameter name is SERVICE_NAME. This name is mainly used by the Oracle client to establish services with Oracle.
When used, it seems that there is no useful value!

Query database service names
Method 1: Select value from V $ parameter where name = 'service _ name ';
Method 2: Show parameter SERVICE_NAME

(Note: In general, the database we use in development is a single database instance, that is, there is only one database in Oracle. At this time, most of them are:
Database Service name = global database name = database name [+ database domain name] = Sid)