How to update multiple rows

Dear All,

I want to update multiple row in single query.I am trying for below
query.I am getting error as

"ERROR: more than one row returned by a subquery used as an expression
SQL state: 21000"

Here is my Query.

update parcelsdata set gid=(select random() * 10),
kasarano=(select kasarano from parcelsdata),
murabano=(select murabano from parcelsdata),
the_geom = (select
(st_dump(st_polygonize(st_union(st_boundary(the_geom), the_line)))).geom as
the_geom from
(select gid,kasarano,murabano,st_linefromtext('LINESTRING('
||(st_xmin(the_geom)-1)::text||'
'||(st_ymax(the_geom)-the_length)||',
'||st_xmax(the_geom)+1||'
'||st_ymax(the_geom)-the_length||')',24047) as the_line, the_geom from
(select 100 as the_length, * from parcelsdata) a) b
where gid = 113 GROUP BY gid,kasarano,murabano)

where kasarano='1' and murabano='119'

Please let me know.I am waiting for your great response.

Thanks and Regards,

Venkat