oracle建表，设置主键，修改属性等

--建表
create table book(
       book_id number(10),
       book_name varchar2(20),
       book_price number(10,2),
       book_author varchar2(20),
       book_publish_time date,
       book_introduction varchar2(100)
);--建表
create table book(
       book_id numb