text: CREATE TABLE 테이블(칼럼1 date);
  INSERT INTO 테이블 VALUES ('2010-01-31'),('2010-01-02'),('2010-02-28'); 
  ALTER TABLE 테이블 rename column  칼럼1 to 칼럼2 ; 
  SELECT * FROM 테이블  order by 1;
  alter 테이블 DROP ATTRIBUTE 칼럼2;
  SELECT * FROM 테이블  order by 1;
  drop class  테이블;