mysql> CREATE TABLE ox(
-> ok char(1) CHECK (ok in('o', 'x'))
-> );
Query OK, 0 rows affected (0.06 sec)
mysql> insert into ox (ok)values('s');
Query OK, 1 row affected (0.00 sec)
mysql> select * from ox;
+------+
| ok |
+------+
| s |
+------+
o,x만 들어가게 제약조건 걸엇는데 s넣으니깐 아무 에러없이 들어가는데 뭐임 ;;
그냥장식