CS145 Assignment #1
Due Wednesday, October 7, 1998
Some Mechanics for Homeworks
For All Students
Assignments are due at
5:00 PM on Wednesday. You are allowed one lateness of up to 48
hours; use that privilege carefully.
For On-Campus Students
Assignments should be turned in during class or at
the course secretary's office: Gates Building room 419.
If you want a receipt for your work, Ms. Lambeth can give you one, but
she often leaves around 4PM.
For SITN students
Assignments due on Wednesday
must be timestamped by the Thursday morning courier to be considered
Like all students, you have one free 48-hour exception.
You should not have to worry about receipts for work, because SITN logs
everything it receives.
Remember: the due time/day of 5PM Wednesday applies to you too, although
we often cannot verify the exact time you delivered your work to your
local pickup point.
However, please do not imagine, say, that it is OK to hand-deliver the
work Thursday morning.
Step 1 of Your PDA (Personal Database Application)
As the course progresses you will be building a substantial
database application for a real-world scenario of your choosing. You
will design schemas for the database, and you will create an actual
database using a relational database management system. You will
populate the database with sample data, write interactive queries and
modifications on the database, and develop user-friendly tools for
manipulating the database.
Your first step is to identify the domain you would like to manage
with your database, and to construct ODL and entity-relationship
schema designs for the data. We suggest that you pick an application
that you will enjoy working with, since you'll be stuck with it for
the whole quarter! In previous years, students who built a database
about something they were interested in--a hobby, material from
another course, a research project, etc.--got the most out of this
part of CS145.
Try to pick an application that is relatively substantial, but not too
enormous. For example, when expressed in the entity-relationship
model, you might want your design to have in the range of five or so
entity sets, and a similar number of relationships. Note that this is
a ballpark figure only! You should certainly include different kinds
of relationships (e.g., many-one, many-many) and different kinds of
data (strings, integers, etc.), but your application need not
necessarily require advanced features such as subclassing in ODL, or
weak entity sets or roles in E/R.
Please put your PDA description at the front of your assignment.
We shall look at these quickly to catch major problems before you have
to hand in Assignment 2.
Also, to make sure we can tell you of a problem with your design,
include your email on this assignment.
database application you propose to work with throughout the course.
Your description should be brief and relatively informal. If there
are any unique or particularly difficult aspects of your proposed
application, please point them out. Your description will be graded
only on suitability and conciseness.
Specify an ODL schema for your proposed database. As always,
don't forget to include keys and inverse relationships.
Specify an entity-relationship diagram for your proposed
database. As always, don't forget to underline key attributes and
include arrowheads indicating the arity of relationships.
Don't forget to save a copy of your PDA for reference as you do
Step 2 of the PDA.
If you are having trouble thinking of an application, or if you are
unsure whether your proposed application is appropriate, please feel
free to consult with one of the course staff.
We would like to design a database to maintain information about hospital
staff, including doctors and nurses, and patients at the hospital.
The information we need includes:
- Staff, including their names, addresses and social-security
- Patients, including their names, addresses, and the name of their
- Patients are each assigned to a ward (room).
- Those staff who are nurses are assigned to zero or more wards.
Each ward has at least one nurse assigned.
- Those staff who are doctors are assigned to zero or more patients.
Patients may or may not have a doctor assigned, and they may have more
than one doctor.
Patients in the same ward may have different doctors but will always
have the same nurse(s).
Specify an ODL schema for this database. In addition to class
definitions with attributes and relationships, don't forget to include
keys and inverse relationships.
Specify an entity-relationship diagram for this database. Don't
forget to underline key attributes and include arrowheads indicating
the multiplicity of relationships.
Give a network-model design for this database.
Note that ``isa'' is not a part of the network model as we have
Do the best you can.
Give a hierarchical-model design for this database,
again handling ``isa'' as best you can.
Note that there is no single right answer to this question, although
some answers may be better than others.
The following E/R diagram is an attempt to design a database in which a
store keeps a permanent record of customers (identified by
social-security numbers) and the items they buy (identified by a unique
item ID assigned by the store).
However, there is a problem with this design, related to our ability to
recover the history of, say, orders by a particular customer for a
Explain what the problem is and propose a solution.
Draw a revised E/R diagram that implements your solution.
Give an ODL description of your revised design.