THE RELATIONAL DATABASE MODEL: ADDITIONAL CONCEPTS - Fundamentals of Database Management Systems - page 155

unique project number, plus a name, budgeted cost,
and due date. Construct a relational database for
ABC Consulting. Hint: You may want to develop
an attribute called ''responsible party'' that can
be either a team or an individual consultant. Each
project has one responsible party that is responsible
for its completion. Or you may want to think of an
individual consultant as a potential ''team of one''
and have the responsibility for each project assigned
to a ''team''

b. The delete rule between the CUSTOMER and
CUSTOMER EMPLOYEE relations is cascade
and an attempt is made to delete the record for
customer 2198 in the CUSTOMER relation?
c. The delete rule between the CUSTOMER and
CUSTOMER EMPLOYEE relations is set-to-
null and an attempt is made to delete the record
for customer 2198 in the CUSTOMER relation?
d. The delete rule between the CUSTOMER and
CUSTOMER EMPLOYEE relations is restrict
and an attempt is made to delete the record
for employee 33779 of customer 2198 in the
CUSTOMER EMPLOYEE relation?
e. The delete rule between the CUSTOMER and
CUSTOMER EMPLOYEE relations is cascade
and an attempt is made to delete the record
for employee 33779 of customer 2198 in the
CUSTOMER EMPLOYEE relation?
f. The delete rule between the CUSTOMER and
CUSTOMER EMPLOYEE relations is set-to-
null and an attempt is made to delete the record
for employee 33779 of customer 2198 in the
CUSTOMER EMPLOYEE relation?

that could then be an individual

consultant or a genuine team.
4. Consider the General Hardware Corp. database
of Figure 6.1. Describe the problem of referen-
tial integrity in terms of the CUSTOMER and
CUSTOMER EMPLOYEE relations if the record
for customer 2198 in the CUSTOMER relation is
deleted. (Assume that no delete rules exist.)
5. In

the General Hardware Corp. database of

Figure 6.1, what would happen if:
a. The delete rule between the CUSTOMER and
CUSTOMER EMPLOYEE relations is restrict
and an attempt is made to delete the record for
customer 2198 in the CUSTOMER relation?

MINICASES

1. Happy Cruise Lines
a. Look at the Happy Cruise Lines database of Chapter
5, Minicase 1 but, for this question, consider only
the SHIP, PORT, and PASSENGER relations. The
company wants to keep track of which passengers
visited which ports on which ships on which dates.
Reconstruct these three relations as necessary and/or
add additional relation(s) as necessary to store this
information.
b. Consider the following data from the SHIP and
CRUISE relations of the Happy Cruise Lines database
of Chapter 5, Minicase 1:

CRUISE Relation

Cruise Start End Cruise Ship

Number Date Date Director Number

21644 7/5/2002 7/12/2002 Smith 009

23007 8/14/2002 8/24/2002 Chen 020

24288 3/28/2003 4/4/2003 Smith 009

26964 7/1/2003 7/11/2003 Gomez 020

27045 7/15/2003 7/22/2003 Adams 012

28532 8/17/2003 8/24/2003 Adams 012

29191 12/20/2003 12/27/2003 Jones 009

29890 1/15/2004 1/22/2004 Levin 020

SHIP Relation

Ship Ship Ship Launch Gross

What would happen if:
i. The delete rule between the SHIP and CRUISE
relations is restrict and an attempt is made to
delete the record for ship number 012 in the
SHIP relation?
ii. The delete rule between the SHIP and CRUISE
relations is restrict and an attempt is made to

Number Name Builder Date Weight

005 Sea Joy Jones 1999 80,000

009 Ocean IV Ajax 2003 75,000

012 Prince Al Ajax 2004 90,000

020 Queen Shirley Master 1999 80,000