Difference between DB_UNIQUE_NAME and GLOBAL_NAME Parameters

[Nalini_sh]

Can anyone tell me that what is the difference between DB_UNIQUE_NAME and GLOBAL_NAME Parameters? and one more thing the global name is not equal to DB_NAME+DB_DOMAIN, why? Please help me out of this.

[Modifier]

Ya, here is the difference between DB_UNIQUE_NAME and GLOBAL_NAME Parameters:
DB_UNIQUE_NAME is used to identify the databases uniquely,i.e usually for dataguard, but it also impacts OMF file locations, whereas the GLOBAL_NAME Parameter is usually active only when GLOBAL_NAMES=true property is set, and this impacts the security for database links.

Database link name must be the same as GLOBAL_NAME for the remote database.

[Reegan]

You can use the ALTER DATABASE statement to change the domain in a database. Note that after the database is created, changing the initialization parameter DB_DOMAIN has no effect on the global database name or on the resolution of database link names. So, after the DB(database) is created, even if you change the GLOBAL_NAME "subcomponent" names, you must still use ALTER DATABASE RENAME GLOBAL_NAME TO database.domain;

[opaper]

Some important points regarding DB_UNIQUE_NAME, DB_DOMAIN, GLOBAL_NAME:
1) DB_UNIQUE_NAME: When you use the above parameter then each database should be different. For e.g. On servers cluster1node1/2 the database’s name is ABCD_FORTWORTH. On servers cluster2node1/2 the databases’s name is ABCD_DALLAS.
2) DB_DOMAIN: Each Streams database, specifies the network domain where the database resides.
3) GLOBAL_NAME: GLOBAL_NAME=TRUE. On each Streams database you need to specify GLOBAL_NAME=TRUE to ensure the database links work correctly. For example, the source database is named ABCD_FORTWORTH.mydomain when you select * from global_name.