text: create database library
  use library
  
  create table books
  (
    book_id char(6)primary key check(book_id like "B[0-9][0-9][0-9][0-9]"),
    book_title char(15)not null,
    auther char(15)not null,
    catagory char(4)check(catagory in("tech","busi","arts")),
    book_price float check(book_price>=0),
    book_qoh int check(book_qoh>=0),
  )