-- 기본키를 포함한 테이블
CREATE TABLE unique_cats (
cat_id INT NOT NULL PRIMARY KEY,
name VARCHAR(100),
age INT
);
-- 다른 방법
CREATE TABLE unique_cats2 (
cat_id INT,
name VARCHAR(100) NOT NULL,
age INT NOT NULL,
PRIMARY KEY (cat_id)
);
CREATE TABLE unique_cats3 (
cat_id INT AUTO_INCREMENT,
name VARCHAR(100) NOT NULL,
age INT NOT NULL,
PRIMARY KEY (cat_id)
);
DESC unique_cats ;
-- 키본키는 중복을 허용하지 않음
INSERT INTO unique_cats (cat_id, name, age) VALUES (1, 'bingo', 2);
-- INSERT INTO unique_cats (cat_id, name, age) VALUES (1, 'bingo', 2); -- 키 중복 오류 발생
INSERT INTO unique_cats (cat_id, name, age) VALUES (2, 'bongo', 3);
INSERT INTO unique_cats (cat_id, name, age) VALUES (3, 'bongo', 3);
INSERT INTO unique_cats (cat_id, name, age) VALUES (999, 'bongo', 3);
SELECT * FROM unique_cats;
-- AUTO_INCREMENT 확인
INSERT INTO unique_cats3 (name, age) VALUES ('Bingo', 1); -- cat_id는 자동 증가
INSERT INTO unique_cats3 (name, age) VALUES ('Bingo', 1);
INSERT INTO unique_cats3 (name, age) VALUES ('Bingo', 1);
INSERT INTO unique_cats3 (name, age) VALUES ('Bingo', 1);
DESC unique_cats3;
SELECT * FROM unique_cats3;