BEGIN;

alter table parkinglot add column music varchar(64);
update parkinglot set music = '' where music IS NULL;
alter table parkinglot alter column music set default '';
alter table parkinglot alter column music set not null;

ALTER TABLE parkinglot add column announce varchar(3);
UPDATE parkinglot SET announce = 'yes' where announce is NULL;
ALTER TABLE parkinglot ALTER column announce SET not NULL;
ALTER TABLE parkinglot ALTER column announce SET default 'yes';
alter table parkinglot add constraint parkinglot_announce CHECK (announce IN ('yes','no'));

COMMIT;
 
