怎么在esqlc中获得某个表的字端的default值啊

[syncpk99]

比如用dbschema获得表test的结构如下：
create table test
(
key serial not null ,action integer,edate datetime year to second,
key_v integer
default 0,
no char(40)
default '',
type integer
default 0,
c_key integer
default 0,
a_key integer
default 0,
sdate datetime year to second,
edate datetime year to second,
password char(16)
default '',
s_flag integer
default 0,
s_state integer
default 0,
primary key (key)
);
我在esqlc下怎么获得a_key的default值呢？
先谢谢了！

[wenlq]

select default from sysdefaults where

tabid = ( select tabid from systables where tabname ='test' )
and colno =
( select colno from syscolumns where
tabid = ( select tabid from systables where tabname = 'test')
and
colname ='a_key')