Oracle® Database SQL Reference 10g Release 2 (10.2) Part Number B14200-02 |
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The Oracle distributed database management system architecture lets you access data in remote databases using Oracle Net and an Oracle Database server. You can identify a remote table, view, or materialized view by appending @dblink
to the end of its name. The dblink
must be a complete or partial name for a database link to the database containing the remote table, view, or materialized view.
See Also:
"Referring to Objects in Remote Databases" for more information on referring to database links
Oracle Net Services Administrator's Guide for information on accessing remote databases
Restrictions on Distributed Queries Distributed queries are currently subject to the restriction that all tables locked by a FOR
UPDATE
clause and all tables with LONG
columns selected by the query must be located on the same database. For example, the following statement raises an error because it selects press_release
, a LONG
value, from the print_media
table on the remote
database and locks the print_media
table on the local
database:
SELECT r.product_id, l.ad_id, r.press_release FROM pm.print_media@remote r, pm.print_media l FOR UPDATE OF l.ad_id;
In addition, Oracle Database currently does not support distributed queries that select user-defined types or object REF
datatypes on remote tables.