select * from main_tab 
where key_id not in (select key_id from ref_tab1)
   and key_id not in (select key_id from ref_tab2)
   and key_id not in (select key_id from ref_tab3)
... /* повторяем для всех detail-таблиц */ ...

select * from main_tab m 
where not exists (select r.key_id from ref_tab1 r where r.key_id = m.key_id)
  and not exists (select r.key_id from ref_tab2 r where r.key_id = m.key_id)
  and not exists (select r.key_id from ref_tab3 r where r.key_id = m.key_id)
... /* повторяем для всех detail-таблиц */ ...

SELECT master.tabname mastertable,
       "->",
       slave.tabname slavetable,
" and not exists (select 1 from " || trim(master.tabname) || 
" where " || trim(get_join_str(sysreferences.constrid)) || ");"
FROM sysreferences,
       systables master,
       sysconstraints masterconstr,
       systables slave,
       sysconstraints slaveconstr,
       outer sysconstraints slaveprim
 WHERE slaveconstr.constrid = sysreferences.constrid
and lower(master.tabname) = lower("<tabname>")  
   AND master.tabid = sysreferences.ptabid
   AND masterconstr.constrid = sysreferences.primary
   AND slave.tabid = slaveconstr.tabid
   AND masterconstr.tabid = master.tabid
   AND slaveprim.tabid = slave.tabid
   AND slaveprim.constrtype = "P"
ORDER BY 1,2;

EXECUTE PROCEDURE ifx_allow_newline('t');
create procedure get_join_str(p_constrid INT)
 returning lvarchar;
 define p_join_str lvarchar;
 define p_master_idxname lvarchar;
 define p_master_tabname lvarchar;
 define p_master_tabid integer;
 define p_slave_idxname lvarchar;
 define p_slave_tabname lvarchar;
 define p_slave_tabid integer;
 define p_idxcolno integer;
 define p_master_colname lvarchar;
 define p_master_colno lvarchar;
 define p_slave_colname lvarchar;
 define p_slave_colno lvarchar;

 SELECT masterconstr.idxname, master.tabname, master.tabid, slaveconstr.idxname, slave.tabname, slave.tabid
   INTO p_master_idxname, p_master_tabname, p_master_tabid, p_slave_idxname, p_slave_tabname, p_slave_tabid
   FROM sysreferences,
        systables master,
        sysconstraints masterconstr,
        systables slave,
        sysconstraints slaveconstr
  WHERE slaveconstr.constrid = sysreferences.constrid
    AND sysreferences.constrid = p_constrid
    AND master.tabid = sysreferences.ptabid
    AND masterconstr.constrid = sysreferences.primary
    AND slave.tabid = slaveconstr.tabid
    AND masterconstr.tabid = master.tabid;

 LET p_join_str = "";
 LET p_idxcolno = 0;
 LOOP
     SELECT ikeyextractcolno(indexkeys, p_idxcolno) INTO p_master_colno FROM sysindices WHERE sysindices.idxname == p_master_idxname;
     SELECT ikeyextractcolno(indexkeys, p_idxcolno) INTO p_slave_colno FROM sysindices WHERE sysindices.idxname == p_slave_idxname;
     IF p_master_colno == 0 OR p_slave_colno == 0 THEN
        EXIT LOOP;
     END IF;
     LET p_idxcolno = p_idxcolno + 1;
     SELECT colname INTO p_master_colname FROM syscolumns
      WHERE tabid = p_master_tabid AND colno = p_master_colno;
     SELECT colname INTO p_slave_colname FROM syscolumns
      WHERE tabid = p_slave_tabid AND colno = p_slave_colno;
     IF LENGTH(p_join_str) > 0 THEN
        LET p_join_str = trim(p_join_str) || "
AND ";
     END IF;
     LET p_join_str = trim(p_join_str) || " " || trim(p_master_tabname) || "." || trim(p_master_colname) ||
                                    " = " || trim(p_slave_tabname) || "." || trim(p_slave_colname);
 END LOOP;

 LET p_join_str = trim(p_join_str);
 return p_join_str;
end procedure;
EXECUTE PROCEDURE ifx_allow_newline('f');