check statement and assertion

I am trying to write a constraint in Oracle 9 with SQL statement. During the creation of the table I have written

check(exist
(select line_no, count(*)
from sections
group by line_no
having count(*)<=4));

but this is not working. Is there anyway to get it worked?

Thank you Received on Wed Nov 26 2003 - 14:07:27 CST