Add constraint on values , Mysql

Question

My table

CREATE TABLE STUDENT ( 
      BCN INT not null,
      Stname varchar(50) not null,
      Sex char(1) not null ,
      primary key (BCN));

Answer 1

From CREATE TABLE:

The CHECK clause is parsed but ignored by all storage engines.

Second:

CREATE TRIGGER SexCheck BEFORE INSERT ON  STUDENT
FOR EACH ROW
BEGIN
    IF New.Sex NOT IN('F', 'M') THEN
    SIGNAL SQLSTATE '10000'
        SET MESSAGE_TEXT = 'check constraint on Student.Sex failed';
    END IF;
END;


INSERT INTO STUDENT(Sex) VALUES ('B');
-- check constraint on Student.Sex failed

SqlFiddleDemo

Answer 2

Use the MySQL ENUM type. "An ENUM is a string object with a value chosen from a list of permitted values that are enumerated explicitly in the column specification at table creation time."

sex ENUM ('M', 'F')