Database Reference
In-Depth Information
Copy
(continued)
21
BookCode
BranchNum
CopyNum
Quality
Price
9627
3
Good
6.50
5
9627
4
Excellent
14.00
1
9627
4
Good
6.50
2
9701
1
Excellent
13.00
1
9701
1
Excellent
13.00
2
9701
2
Excellent
13.00
1
9701
3
Fair
4.00
1
9701
3
Fair
4.00
2
9701
3
3
Good
7.25
9701
4
1
Excellent
13.00
9701
4
2
Poor
1.55
9882
3
Excellent
6.99
1
9882
3
Good
3.75
2
9882
3
Excellent
6.99
3
9883
2
Excellent
5.99
1
9883
2
Excellent
5.99
2
9883
2
Fair
1.95
3
9883
4
Good
3.99
1
9883
4
Excellent
5.99
2
9931
1
Excellent
13.00
1
9931
1
Excellent
13.00
2
FIGURE 1-18
Sample data that relates books to authors and books to branches for Henry Books
(continued)
Q&A
Question: To check your understanding of the relationship between authors and books, answer the following
questions: Who wrote Black House? (Make sure you list the authors in the correct order.) Which books did
Toni Morrison write?
Answer: Stephen King and Peter Straub wrote Black House. To determine who wrote Black House, first
examine the topic table (see Figure 1-17) to find its book code (9611). Next, look for all rows in the Wrote
table in which the book code is 9611. There are two such rows. In one row, the author number is 5, and in
the other row, the author number is 6. Then look in the Author table to find the authors who have been
assigned the numbers 5 and 6. The answer is Peter Straub (5) and Stephen King (6). In the Wrote table, the
sequence number for author number 5 is 2, and the sequence number for author number 6 is 1. Thus, listing
the authors in the proper order results in Stephen King and Peter Straub.
Toni Morrison wrote Beloved, Jazz, and Song of Solomon. To find the topics written by Toni Morrison,
look up her author number in the Author table and find that it is 1, then look for all rows in the Wrote table
for which the author number is 1. There are three such rows. The corresponding book codes are 138X, 6128,
and 9627. Looking up these codes in the topic table, you find that Toni Morrison wrote Beloved, Jazz, and
Song of Solomon.
