-- Your SQL goes here

alter table daka
    drop column daka_date;

alter table daka
    add start_date timestamp not null;

alter table daka
    drop column student_id;

alter table daka
    rename column beizhu to "desc";

alter table daka
    add duration_days int not null;

alter table daka
    add name varchar not null;

alter table daka
    add owner_id varchar not null;