Whats the use of having default and not null constraint on the same column, wouldn't default make that column NOT NULL..
CREATE TABLE AttribBill (
AtBill_ID number PRIMARY KEY ,
AtBill_Type number NOT NULL,
AtBill_Date date NULL ,
AtBill_Invoiced number Default 20 Not Null);
AtBill_Invoiced number Default 20 Not Null... here this column has both... also

When do you do default and NULL on the same column ??

SAy
AtBill_Invoiced number Default 20 Null

Isn't this technically wrong ?

Thanks
Sonali