dblink_open — opens a cursor in a remote database
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
dblink_open() opens a cursor in a remote database.
The cursor can subsequently be manipulated with
dblink_fetch() and dblink_close().
connnameName of the connection to use; omit this parameter to use the unnamed connection.
cursornameThe name to assign to this cursor.
sql
The SELECT statement that you wish to execute in the remote
database, for example select * 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.
Returns status, either OK or ERROR.
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.
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)