Oracle 9.2i unix timestamp sekunden in datum umrechnen

CREATE OR REPLACE FUNCTION unixts2date( n_seconds 	IN 	PLS_INTEGER) 
										RETURN 			DATE 
IS
	unix_start	DATE 			:= TO_DATE('01.01.1970','DD.MM.YYYY');
	unix_max   	PLS_INTEGER 	:= 2145916799;
	unix_min	PLS_INTEGER 	:= -2114380800;
	
BEGIN

	IF n_seconds > unix_max THEN
	   RAISE_APPLICATION_ERROR( -20901, 'UNIX timestamp too large for 32 bit limit' );
	ELSIF n_seconds < unix_min THEN
	    RAISE_APPLICATION_ERROR( -20901, 'UNIX timestamp too small for 32 bit limit' );
	ELSE
		RETURN unix_start + NUMTODSINTERVAL( n_seconds, 'SECOND' );
	END IF;

EXCEPTION
	WHEN OTHERS THEN
		RAISE;
END;
/

SQL> alter session set nls_date_format = 'dd.mm.yyyy hh24:mi:ss';

Session wurde geandert.

SQL> select unixts2date( 1157486783 ) from dual;

UNIXTS2DATE(1157486
-------------------
05.09.2006 20:06:23