dblink_open
dblink_open — opens a cursor in a remote database
Synopsis
dblink_open(text cursorname, text sql [, bool fail_on_error]) returns text
dblink_open(text connname, text cursorname, text sql [, bool fail_on_error]) returns text
Description
dblink_open() opens a cursor in a remote database. The cursor can subsequently be manipulated with dblink_fetch() and dblink_close().
Arguments
connname-
Name of the connection to use; omit this parameter to use the unnamed connection.
cursorname-
The name to assign to this cursor.
sql-
The
SELECTstatement that you wish to execute in the remote database, for exampleselect * from pg_class. fail_on_error-
If true (the default when omitted) then an error thrown on the remote side of the connection causes an error to also be thrown locally. If false, the remote error is locally reported as a NOTICE, and the function's return value is set to
ERROR.
Return Value
Returns status, either OK or ERROR.
Notes
Since a cursor can only persist within a transaction, dblink_open starts an explicit transaction block (BEGIN) on the remote side, if the remote side was not already within a transaction. This transaction will be closed again when the matching dblink_close is executed. Note that if you use dblink_exec to change data between dblink_open and dblink_close, and then an error occurs or you use dblink_disconnect before dblink_close, your change will be lost because the transaction will be aborted.
Examples
SELECT dblink_connect('dbname=postgres options=-csearch_path=');
dblink_connect
----------------
OK
(1 row)
SELECT dblink_open('foo', 'select proname, prosrc from pg_proc');
dblink_open
-------------
OK
(1 row)