Oracle's DB Link

Links between databases are built on database link. To create a DB link, you must first set up the link string on each database server.

1, configure TNS, $ORACLE _home/network/admin/tnsname.ora

10gstandby =

(DESCRIPTION =

(address = (PROTOCOL = TCP) (HOST = hfcc-kf-3068) (PORT = 1522))

(Connect_data =

(SERVER = dedicated)

(service_name = 10gstandby)

）

）

2, create a database link,

Create Public database link Db_link_name connect to targetdatabaseusername identified by Targetdatabasepassword using ' Tar Getdatabasesidname ';

Note: Targetdatabasesidname the database connection string defined inside the Tnsnames.ora file on the host where the Oracle database resides.

Sql>create Public Database link DVD connect to system identified by system using ' orcl10g ';

or use:

Create Public database link Link_name

Connect to USER identified by PWD

Using ' (DESCRIPTION =

(Address_list =

(address = (PROTOCOL = TCP) (HOST = 192.168.1.1) (PORT = 1521))

）

(Connect_data =

(service_name = ORCL)

）

）';

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We created a link DVD with the system user and orcl10g database, and we queried the DVD data:

Sql>select * from All_users@dvd;

This allows the local and remote data to be processed as a whole.

3, to establish synonyms, in order to make more transparent about distributed operations, the Oracle database has synonyms for objects synonym

Sql>create synonym syntest for all_users@dvd;

So we can use Syntest to replace the Distributed link operation All_users@dvd with @ symbol;

4, see all the database links:

Sql>select owner,object_name from dba_objects where object_type= ' DATABASE LINK ';

5. View database connection

Sql> Select owner, db_link from Dba_db_links;

Ower Db_link

Public DVD. Regress. Rdbms. DEV. US. Oracle.com

6. Delete database connection

First view the database connection from step 5th to get the name of the Db_link

Sql>drop Public Database link DVD. Regress. Rdbms. DEV. US. Oracle.com

Database connection has been discarded

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