delete from child_table, parent_table where
child_table.parent_id=parent_table.parent_id

Hi vaishali have u executed the query it is not working

delete from child_table where values=...
on delete cascade..
U have to set the foreign  key as the parent super key

Better you create a Trigger on child table like this one

CREATE TRIGGER trDelTrigger ON [dbo].[ChildTable] 
FOR  DELETE 
AS
DELETE FROM ParentTable WHERE ParentTable.IdColumn=
(SELECT Deleted.IdColumn FROM Deleted)

I think using ON DELETE CASCADE we can delete  the records 
from both child and parent table

create table employee(id int references authors(au_id) ON
DELETE CASCADE,firstname(30))



this is chilld table .in this query use on first child table
constraints values delete next parent table constrains value
delete ...  this is   ON DELETE CASCADE CONCEPT

delete from c from child c inner join parent
on c.childid = parentid

delete details  from details inner join master on 
details.keyid=master.keyid