20230317수업내용

desc board;
desc login;

create table member(
	id varchar(20) primary key,
    password varchar(30) not null,
    name varchar(10) not null,
    birthday date not null,
    gender varchar(5) not null,
    email varchar(10),
    phone varchar(15)
    );
    
    
create table board2(
no int primary key auto_increment,
title varchar(10) not null,
content varchar(20),
id varchar(10),
regdate datetime default now(),
count int,
good int,
-- meber 테이블의 id열이 부모열, board테이블의 id 열이 자식열
foreign key(id) references member(id)
);
/* alter table board add constraint foreign key(id) references member(id); 테이블에 추가를 하지 못하고 테이블에 나중에 추가할때*/
desc board2;


insert into member values ('abcd','1234','정자바','1998-03-17','남','abcd@a.com','01012341234');
insert into member values ('zzzz','1234','정자바','1998-03-17','남','abcd@a.com','01012341234');
alter table member modify column email varchar(20);
desc member;
desc board2;

insert into board2(title,content,id) values('안녕하세요','오늘 정모 있습니다.','zzzz');
select * from board2;
alter table board2 modify count int default 0;
desc board2;
alter table board2 modify good int default 0; 

select * from board2;
select * from board2 where no = 2;  -- title 을 클릭하면
update board2 set count = count + 1 where no =2;
desc board2;

start transaction;
select * from board2 where no = 2;  -- title 을 클릭하면
update board2 set count = count + 1 where no =2;
-- 정상적으로 select랑 update가 됨