Hello all, Is there any sitrualtion in which a NOT NULL filed is displayed as null when we issue : DESC <<tablename>>. I have a table tab1 with a field col1. When i DESC tab1, it displays col1 as NULL. However all th values for col1 are not null. So i try to modify this column to NOT NULL. Now it gives the error that col1 is already NOT NULL. Why is this so???