key constraint

From: Jian Xu <Jian.Xu_at_mcs.vuw.ac.nz>
Date: Sat, 14 Apr 2001 17:43:37 +1200
Message-ID: <987227398.2119731143@news.mcs.vuw.ac.nz>

i'm doing a database project, and met one question about the key constraints. what the question asked is simply " Drop key constraint from the table Cust_Order relation."
  i just dropped the primary key constraint for that relation, but i'm confused with the "not null" constraint. do i need to drop that constraint also?   does any one familiar with the key constraint definition to help me ?   the relation definition below:
  Table name : Cust_Order primary key : OrderID OrderID integer 4 n

OrderDate  Date       y
CustomerID int 4      n

  here 'y' means can be null, n means can be not null. the first column is attribute name and the second is data type accordingly.

 tks and rgs,
jxu Received on Sat Apr 14 2001 - 00:43:37 CDT