Oracle中的global_name和db domain

Oracle中的global_name和db domain，alter database rename global_name to xx并不影响db_domain参数, 而创建db link时使用的是g

Oracle中的global_name和db domain

determine the current database global name:

CONNECT SYSTEM@sales.us.example.com

GLOBAL_NAME;

GLOBAL_NAME

----------------------------------------------------------------------------

SALES.US.EXAMPLE.COM

2. You query the V$PARAMETER view to determine the current setting for the DB_DOMAIN initialization parameter:

V$PARAMETER

NAME VALUE

--------- -----------

db_domain US.EXAMPLE.COM

3. You a partially-specified global name:

The database expands the global database name for this link by appending the domain part of the global database name of the local database to the name of the database specified in the link.

4. You query USER_DB_LINKS to determine which domain name the database uses to resolve the partially specified global database name:

SELECT DB_LINK FROM USER_DB_LINKS;

DB_LINK

------------------

HQ.US.EXAMPLE.COM

This result indicates that the domain part of the global database name of the local database is us.example.com. The database uses this domain in resolving partial database link names when the database link is created.

5. Because you have received word that the sales database will move to Japan, you rename the sales database to sales.jp.example.com:

GLOBAL_NAME TO sales.jp.example.com;

GLOBAL_NAME;

GLOBAL_NAME

----------------------------------------------------------------------------

SALES.JP.EXAMPLE.COM

6. You query V$PARAMETER again changed, although you renamed the domain part of the global database name:

V$PARAMETER

  

NAME VALUE

--------- -----------

db_domain US.EXAMPLE.COM

This result indicates that the GLOBAL_NAME statementthe DB_DOMAIN initialization parameter

7. You query USER_DB_LINKS to see how the database resolves the domain part of the global database name of supply:

SELECT DB_LINK FROM USER_DB_LINKS;

DB_LINK

------------------

HQ.US.EXAMPLE.COM

SUPPLY.JP.EXAMPLE.COM

This result indicates that the The database does not use the DB_DOMAIN initialization parameter setting when resolving the partial link name.

8. You then receive word that your previous information was faulty: sales will be in the ASIA.JP.EXAMPLE.COM domain, not the JP.EXAMPLE.COM domain. Consequently, you rename the global database name as follows:

GLOBAL_NAME TO sales.asia.jp.example.com;

GLOBAL_NAME;

GLOBAL_NAME

----------------------------------------------------------------------------

SALES.ASIA.JP.EXAMPLE.COM

You query V$PARAMETER to again check the setting for the parameter DB_DOMAIN:

V$PARAMETER

  

NAME VALUE

---------- -----------

db_domain US.EXAMPLE.COM

The result indicates that the domain setting statements.

9. Finally, you create a link to the warehouse database and again query USER_DB_LINKS to determine how the database resolves the partially-specified global name:

SELECT DB_LINK FROM USER_DB_LINKS;

DB_LINK

------------------

HQ.US.EXAMPLE.COM

SUPPLY.JP.EXAMPLE.COM

WAREHOUSE.ASIA.JP.EXAMPLE.COM

Again, you see that the database uses the domain part of the global database name of the local database to expand the partial link name during link creation.

由此说明, alter database rename global_name to xx并不影响db_domain参数, 而创建db link时使用的是global_name而不是db_domain.

，