In mysql, the not null constraint is used to restrict a column to not accept null values.the not null constraint allows a column to always contains a value which means you cant not insert/update a ...

Constraint/SQL -- Constraint drop table snapdeal_orders; create table snapdeal_orders ( order_Id int not null, -- now we can not add null value in column order_id , not null constraint order_date date ...

See also tests that manipulates with NULL fields/domains and check results: CORE1518 Adding a non-null restricted column to a populated table renders the table inconsistent; CORE4453 (Regression: NOT ...