Abnormal Psychology The causes of abnormal behavior are very complex. Psychological disorders can be caused by nature (biology/genetics) or nurture (psychosocial factors). Do you think one causes more than the other or is there a balance?
Abnormal Psychology
The causes of abnormal behavior are very complex. Psychological disorders can be caused by nature (biology/genetics) or nurture (psychosocial factors). Do you think
one causes more than the other or is there a balance?
CS 4163/6523: Introduction to Database Systems
Homework 1
Percentage of course grade: 10
Problem 1 (10 points): Figure 1 shows three ER diagrams for a university registrar’s office. List the merits of each of the
three ER diagrams to model this miniworld by citing ease of answering specific queries, and argue in favor of one of
the alternatives. In particular, consider the ease of answering certain queries in each of the three diagrams and storage
requirements.
class instructor
course # dept
enrollment
name
student
SSN name
time
takes teaches
id
grade
class instructor
course # dept
enrollment
name
student
SSN name
time place
takes teaches
id
grade
class
course # dept
enrollment
student
SSN name
time place
takes
grade
instructor
Rooms
Bldg Room #
Meets in
M N N 1
M N N 1
N
1
M N
Figure 1
(i)
(ii)
(iii)
Problem 2 (25 points): Design an EER schema for a database for a social networking application with the following
specifications:
• Each user has a unique username, a password, and a profile consisting of several attributes like name, age, etc.
(you should choose the profile attributes based on your preferences).
• Each user can subscribe to several “shared space/programs”. A shared space/program can be either a Group, an
Event, or an Application. Choose distinct attributes for Groups, Events, Applications based on your experience
and ensure that each has some key attributes.
• Each user owns several “private spaces.” Each private space has a ID1
, date of creation, and size attribute.
1
IDs of private spaces can be repeated for different users but is unique within one user’s collections
Different kind of private spaces include Message board, Photo,
Video, Blog. Choose specific attributes for each of
these private spaces based on your experience.
• Other users can comment on any private space of a given user. They can also apply tags to any private space,
where a tag has a unique tag id, a label, and can belong to multiple categories.
• Users can become friends with other users. You need to store the date when two users became friends.
Specify key attributes of each entity type and structural constraints on each relationship type. Clearly identify any
specialization and union types. Note any unspecified requirements, and make appropriate assumptions to make the
specification complete.
Problem 3 (20 points): Exercise 3.19 in the textbook.
Problem 4 (10 points): Correct all mistakes and fill in omissions in the following E-R diagram:
Savings Checking
ChecksPerMo MinBalance
o
Person Company U
SSN TaxID
Cust−
Banker
Name Payment#
borrower
Loan
payment
Src_acc#
Installment
Date Amount
Name
Sex
Balance
Access−date
Acc#
Employee
SSN
Name
Dependents
of
Dependent
Customer
Address Loan#
Amount
Loan
1
1
M
N
1
N
Works
under
N
1
1 N 1 N
Account
DOB
Depositor
CustID
Problem 5 (20 points): Represent the EER schema of Figure 4.12 in UML notation (ignore the UNION type).
Problem 6 (15 points): Map the EER schema in Figure 4.12 into a relational schema. Clearly specify all primary and
foreign keys.