create table computers（ comNo number(4)  constraint PK_comp primary key, compModel varchar2(64) constraint unique_comp unique, buyTime date, price number(12,2) constraint ch_price check( price>0 and price<=300000), owner varchar2(32));DECLARE  i number := 0;BEGIN  for i in 1 .. 3000 loop    insert into computers      (comNo, compModel, buyTime, price, owner)    values      (i, '8' + i, to_date('' + sysdate, 'YYYY-MM'), i, 'zhangsan');    --dbms_output.put_line(i);  end loop;  commit;END;