Some code about the knowledge tree software in the database aspect

To this project, I can only say, can't make it ...

If you can knock the code out for one weeks, it's not going to work.

The main reason or because we are too strict rules, look at the book said Waterfall model did not finish the next step, it really did so, the results to the 6th, 7 weeks in the instructions on the walk, this is really a sad story ...

Here is my definition of the database:

drop table if exists book;

drop table if exists Student;

drop table if exists Teacher;

CREATE TABLE book (
zhang_id int,
jie_id int,
book_id int,
Zhang_name varchar (50),
Jie_name varchar (50),
Book_name varchar (50),
Book_view text,
Primary KEY (zhang_id,jie_id,book_id));

CREATE TABLE Teacher (
teacher_id varchar (50),
Teacher_name varchar (50),
Teacher_passward varchar (50),
Primary KEY (teacher_id));

CREATE TABLE Student (
student_id varchar (50),
Student_name varchar (50),
Student_passward varchar (50),
Primary KEY (student_id));

Some code about the knowledge tree software in the database aspect