Chapter 4, Problem 7PE

Explanation of Solution

Query

create table student

(ID varchar(5),

name varchar(20) not null,

dept_name varchar(20),

tot_cred numeric(3,0) check(tot_cred>=0),

primary key(ID),

foreign key (dept_name) references department

    on delete set null);

create table takes

(ID varchar(5),

course_id varchar(8),

section_id varchar(8),

semester varchar(6),

year numeric(4,0),

grade varchar(2),

primary key(ID, course_id, section_id, semester, year)

foreign key(course_id, section_id, semester, year) references section

        on delete cascade

foreign key(ID) references student

        on delete cascade);

create table advisor

(i_id varchar(5),

s_id varchar(5),

primary key(s_id),

foreign key(i_id) references instructor(id)

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