Advanced Database Technologies
(IT5020)
Assignment 1- Relational Model
Faculty of Graduate Studies and Research
Sri Lanka institute of Information Technology
Course
: MSc (IT) — Advanced Database Technologies
Instructor
: Prasanna S. Haddela
Batch
: 2020 June
Name
:Isuru prabath Subasinghe
Email
: Prabath230@gmail.com
Contact Number : 071-6863995
Exercise 1 – Conceptual Modeling.
Exercise 1 – Conceptual Modeling
1. Recommend at least 5 improvements,
I.
II.
III.
IV.
V.
Entities should be kept in singular.
Adding cardinality ratio.
Mentioning derived, multivalued, composite attributes clearly.
Mapping week entity
Generalization should be mentioned.
2. design traps
Chasm trap between– author – book - published book
3. different ways of modelling same scenario.
I.
II.
We can use different Generalization method like Superclass subclass method.[1]
Category or Union
Exercise 2 – Mapping from E-ER to Relational Model
Author
author_Id
Items
f-name
item_numb
l-name
title
other
description
Books
item_numb
Book_ID
author_Id
Text Book
Book_ID
Textbook_ID
Semester
Published Books
Book_ID
pubbook_ID
edition
Published Book Type
pubbook_ID
ISBN
edition
Year
Section
cover
Year publishe
publis
Periodicals
item_numb
Periodicals_ID
publisher
frequenc
Periodical Type
Periodical Type_ID
Periodicals_ID
date
Periodical Type
News Paper
Periodicals_ID
Newspaper_name
NewspaperID
Magazine
Periodicals_ID
Magazine_name
MagID
Software & Manuals
SoftMan_ID
item_numb
manufacture
manufacture
Members
library_id
f-name
l-name
other_name
remarks
password
e-mail
phone
Members workpalce
library_id
office_no
floor
campus
Members address
library_id
Address_L1
Address_L2
Address_L3
Member Type
library_id
Type
Loan
library_id
Payment
payId
LoadID
fine paid
Date returne
amount
Date
library_id
C_itemID
Date
library_id
item_numb
manufacture
Textbook_ID
Semester
Due date
datetime_
borrowed
fine
C_itemID
SoftMan_ID
Copy of Item
payId
LoadID
C-Software & Manual
C_SoftMan_ID
manufacture
SoftMan_ID
C-Text
C_Book_ID
Year
Section
C_itemID
Textbook_ID
C-Published Book Type
C_pubbook_ID
ISBN
edition
cover
Year
publishe
publis
C_itemID
ISBN
C-Periodical Type
C_Periodical Type
Periodicals_ID
publisher
frequenc
C_itemID
Periodical
Type_ID
Exercise 3 – SQL - SELECT
Consider the following relational schema. An employee can work in more than one department;
the pct-time field of the Works relation shows the percentage of time that a given employee
works in a given department.
Emp( eid: integer, ename: string, age: integer, salary: real)
Works( eid: integer, did: string, pct-time: integer)
Dept( did: string, budget: real, managerid: integer)
Write the following queries in SQL:
1. Print the names and ages of each employee who works in both the Hardware department and
the Software department.
SELECT e.ename, e.age FROM Emp e
INNER JOIN works w ON e.eid = w.eid
INNER JOIN Dept d ON w.eid = d.did
2. Print the name of each employee whose salary exceeds the budget of all of the departments
that he or she works in.
SELECT E.ename
FROM Emp E
WHERE E.salary > ALL (SELECT D.budget
FROM Dept D, Works W
WHERE E.eid = W.eid AND D.did = W.did)
3. Find the managerids of managers who manage only departments with budgets greater than
$1,000,000.
SELECT distinct d. managerid FROM dept d
Where 1000000<ALL ( SELECT d2.budget FROM dept d2 WHERE d2.managerid= d.
managerid)
4. Find the enames of managers who manage the departments with the largest budget.
SELECT E.ename
FROM Emp E
WHERE E.eid IN (SELECT D.managerid
FROM Dept D
WHERE D.budget >= ALL (SELECT D2.budget FROM Dept D2))
5. If a manager manages more than one department, he or she controls the sum of all the
budgets for those departments. Find the managerid of managers who control more
than $5,000,000.
SELECT M. managerid
FROM Emp M
WHERE M.sid IN (SELECT M2.sid
FROM Emp M2, Dept D
WHERE M2.sid = D.managerid AND D.budget < 5000000
EXCEPT
SELECT M3.sid
FROM Emp M3, Dept D2
WHERE M3.sid = D2.managerid AND
D2.budget <= 5000000)
6. Find the managerid of managers who control the largest amount.
SELECT distinct d. managerid FROM dept d
Where 5000000<ALL (SELECT d2.budget FROM dept d2 WHERE d2.managerid= d.
managerid)
Resources
[1] “Enhanced Entity Relationship Model (EER Model).” https://www.tutorialride.com/dbms/enhancedentity-relationship-model-eer-model.htm (accessed Feb. 20, 2021).