Description
Examine the following relation and its attributes and answer the following questions. Assume these are the values for “all time”. Assume girls with the same name are the same person.
GIRL GROUP AGE GAME CATEGORY PRICE
Charlotte 5 year olds 5 Mirror Makeup 4.88
Susan 6 year olds 6 Lipstick Makeup 5.95
Jane 5 year olds 5 Chess Games 7.55
Susan 6 year olds 6 Checkers Games 5.95
Susan 6 year olds 6 Mirror Makeup 4.88
Carrie 6 year olds 6 Lipstick Makeup 5.95
Jacqueline 5 year olds 5 Visual Basic Prog. Languages 199.99
1) Is this relation in at least 1NF? Why or why not?
2) What is the primary key of the initial relation (assume the values shown are the only possible tuples for all time)? Remember that a primary key must be unique and not null.
3) Describe the specific data anomalies that exist if we DELETE the tuple containing Jacqueline.
4) Draw a functional dependency diagram for the initial relation. This diagram should agree with the primary key you selected in above.
5) Based on your diagram, what normal form is the initial relation in? Why?
6) If necessary, decompose the initial relation into a set of non-loss 3NF relations by showing the relations, attributes, and tuples. Show complete relations with attribute headings and all data values in the tuples of your relations. Determine the number of 3NF relations you end up with after normalization, write this number, and then circle the number.
Grading rubric
Attributes
Meets
Does Not Meet
Normal form
20 points
Student correctly identifies normal form of initial relation
0 points
Major error in identification of normal form or not specified
Primary key
25 points
Student correctly identified primary key of initial relation
0 points
Major error with identification of primary key or not specified
Data anomalies
15 points
Student correctly describes data anomalies
0 points
Major errors with description of data anomalies or not specified
Functional dependency diagram
15 points
Student correctly develops functional dependency diagram of initial relation
0 points
Major errors developing functional dependency diagram or not specified
Normalized 3NF relations
25 points
Student correctly develops the proper set of 3NF relations via normalization
0 points
Major errors in development of proper set of 3NF relations or not specified