[DDL] 기본키 제약 조건을 설정하는 다양한 방법

-- 1
CREATE TABLE product(
    prdNo VARCHAR(10) NOT NULL PRIMARY KEY,
    prdName VARCHAR(30) NOT NULL,
    prdPrice INT,
    prdCompany VARCHAR(30)
);

-- 2
CREATE TABLE product2(
    prdNo VARCHAR(10) NOT NULL,
    prdName VARCHAR(30) NOT NULL,
    prdPrice INT,
    prdCompany VARCHAR(30),
    PRIMARY KEY(prdNo)
);

-- 3
CREATE TABLE product3(
    prdNo VARCHAR(10) NOT NULL,
    prdName VARCHAR(30) NOT NULL,
    prdPrice INT,
    prdCompany VARCHAR(30),
CONSTRAINT PK_product_prdNo PRIMARY KEY(prdNo)
);​