Not Null Constraints

Not Null:

Not Null is a domain integrity.
It ignores Null Values.

Syntax:

create table course345( CId Number, CName varchar(20), gender char(1) Not null);

Table Created

insert into course345 values(1,'parthi','m');
insert into course345 values(2,'karthi','m');

Two Rows Created

insert into course345 values(1,'arthi',null);

When run this above query its redirect to the below error

ORA-01400: cannot insert NULL into ("HR"."COURSE345"."GENDER")