CS145 Assignment #1
Due Tuesday, April 15, 1997
Reminder for on-campus students: Assignments are due at
5:00 PM on Tuesday. You are allowed one lateness of up to 48
hours; use that privilege carefully.
Assignments should be turned in during class or at
the course secretary's office: Gates Building room 495.
Reminder for SITN students: Assignments due on Tuesday
must be timestamped by the Wednesday morning courier to be considered
Like the on-campus students, you have one free 48-hour exception.
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.
Write a short (approximately one paragraph) description of the
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.
This exercise depends on a Exercise 2.1.1, whose
on-line solution is at URL
You should explain the changes necessary for each of the four parts; you
do not have to redo the complete ODL specification for each part.
This exercise depends on Exercise 2.2.1, whose
solution is at URL
Again, explain the changes necessary for each of the four parts; you
do not have to redo the complete E/R diagram for each part.
This exercise uses Exercise 2.1.5, whose solution is
We would like to design a database to maintain information about the
The information we need includes:
- Hosts on the web, including their IP addresses, names, location, and
person responsible for their operation.
- Directories accessible to the web, including their name,
their host (if a root
directory) or parent directory (if not), their subdirectories, and their
- Files, including their name and parent directory.
- Links, connecting one file (where the anchor is) to another (the
URL found in the anchor).
- Accesses, including the accessing host, the accessed host, and the
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.
Note that there is no single right answer to this question, although
some answers may be better than others.