Answered: with recursive rec_prereq(course_id,…

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Related questions

Question

Modify the recursive query in Figure 5.16 to define a relation
prereq_depth(course_id, prereq_id, depth) where the attribute depth indicates how many levels of intermediate prerequisites there are between the course and the prerequisite. Direct prerequisites have
a depth of 0. Note that a prerequisite course may have multiple depths and thus
may appear more than once.

with recursive rec_prereq(course_id, prereq_id) as (
select course_id, prereq_id
from prereq
union
select rec_prereq.course_id, prereq.prereq_id
from rec-prereq, prereq
where rec-prereq.prereq_id = prereq.course_id
select *
from rec-prereq;
Figure 5.16 Recursive query in SQL.

Expert Solution

Trending now

This is a popular solution!

Step by step

Solved in 2 steps

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.

Similar questions