mysql NOT NULL constraint syntax

mysql NOT NULL constraint syntax

Role: constraints force the column does not accept NULL values.

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Description: the NOT NULL constraint mandatory field always contains a value. This means that if you do not add value to the field, you can not insert a new record or update the record.

mysql NOT NULL constraints example

// mandatory "Id_P" column and the "LastName" column does not accept NULL values 
CREATE TABLE Persons (Id_P int NOT NULL , LastName varchar (255) NOT NULL, FirstName varchar (255), Address varchar (255), City varchar (255) );