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().
Name of the connection to use; omit this parameter to use the unnamed connection.
The name to assign to this cursor.
The SELECT statement that you wish to execute in the remote database, for example select * from pg_class.
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.
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.