dblink_exec — executes a command in a remote database
dblink_exec(text connname, text sql [, bool fail_on_error]) returns text dblink_exec(text connstr, text sql [, bool fail_on_error]) returns text dblink_exec(text sql [, bool fail_on_error]) returns text
    dblink_exec executes a command (that is, any SQL statement
    that doesn't return rows) in a remote database.
   
    When two text arguments are given, the first one is first
    looked up as a persistent connection's name; if found, the command
    is executed on that connection.  If not found, the first argument
    is treated as a connection info string as for dblink_connect,
    and the indicated connection is made just for the duration of this command.
   
connnameName of the connection to use; omit this parameter to use the unnamed connection.
connstr       A connection info string, as previously described for
       dblink_connect.
      
sql       The SQL command that you wish to execute in the remote database,
       for example
       insert into foo values(0, 'a', '{"a0","b0","c0"}').
      
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 the command's status string or ERROR.
   
SELECT dblink_connect('dbname=dblink_test_standby');
 dblink_connect
----------------
 OK
(1 row)
SELECT dblink_exec('insert into foo values(21, ''z'', ''{"a0","b0","c0"}'');');
   dblink_exec
-----------------
 INSERT 943366 1
(1 row)
SELECT dblink_connect('myconn', 'dbname=regression');
 dblink_connect
----------------
 OK
(1 row)
SELECT dblink_exec('myconn', 'insert into foo values(21, ''z'', ''{"a0","b0","c0"}'');');
   dblink_exec
------------------
 INSERT 6432584 1
(1 row)
SELECT dblink_exec('myconn', 'insert into pg_class values (''foo'')',false);
NOTICE:  sql error
DETAIL:  ERROR:  null value in column "relnamespace" violates not-null constraint
 dblink_exec
-------------
 ERROR
(1 row)