MySQL DEFAULT Constraint

 

MySQL DEFAULT Constraint

The DEFAULT constraint is used to set a default value for a column. The default value will be added to all new records, if no other value is specified.

DEFAULT on CREATE TABLE

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    City varchar(255) DEFAULT 'Sandnes'
);

DEFAULT on ALTER TABLE

ALTER TABLE Persons
ALTER City SET DEFAULT 'Bhadrapur';

DROP a DEFAULT Constraint

ALTER TABLE Persons
ALTER City DROP DEFAULT;