컬럼 및 제약 조건 추가

설명

컬럼 및 제약 조건은 ALTER 구문의 ADD [ATTRIBUTE | COLUMN] 예약어를 사용하여 추가할 수 있다.

구문

ALTER [ table_type ] table_name
ADD [ ATTRIBUTE | COLUMN ] attr_definition | table_constraint_definition
[ { , attr_definition | class_constraint }_ ]
[ INHERIT resolution [ { , resolution }_ ] ] [ ; ]

ALTER [ table_type ] table_name
ADD CLASS ATTRIBUTE table_attr_definition [ {, class_attr_definition }_ ]
[ INHERIT resolution [ { , resolution }_ ] ] [ ; ]

table_type:
[TABLE | CLASS]
[VIEW | VCLASS]

resolution:
TABLE ] attr_mthd_name OF superclass_name [ AS alias ]
table_constraint_definition :
[ CONSTRAINT constraint_name ] [ UNIQUE | PRIMARY KEY | FOREIGN KEY]
(attribute_name [{, attribute_name } ...])

예제

ALTER TABLE athlete ADD COLUMN age INT;
ALTER TABLE athlete ADD COLUMN age INT DEFAULT 0 NOT NULL;
ALTER TABLE athlete ADD COLUMN retire CHAR(1) SHARED 'N';
ALTER TABLE athlete ADD COLUMN phone VARCHAR(13) DEFAULT '000-0000-0000';

ALTER TABLE company ADD CONSTRAINT pk_id PRIMARY KEY (comp_id);
ALTER TABLE nation ADD CONSTRAINT u_name UNIQUE (name);