Jian Xu
04-14-01, 02:43
| 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 |