In MySQL, by default a column can hold NULL values, the
NOT NULL constraint on the other hand restrict column to NOT to accept NULL values. The
NOT NULL constraint forces the column to always accept a value. Using
NOT NULL constraint you can make sure a column cannot have a NULL value.
In the above example, we are creating new table called "tblCustomer" using
NOT NULL constraint. The
NOT NULL constraint enforces column "custId", firstName", "lastName" and "address" to NOT to accept NULL values.
You can use MySQL Command Line Client to enforces column to NOT to accept NULL values.