CSI2132 Assignment 3 solution

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A. Relational Algebra
Consider the following extended schema about Kids (Campers) that register for
Camps in Adventures and Science in Engineering at uOttawa.
Camper(CName : string, Age : string,Email : string, tshirt : string, Fee : real)
Camp(CampID : int, CampTitle : string,EmpID : int, StartDate : date, Year : date)
Signup(CName : string, CampID : string)
Mentor(EmpID : int, Name : string,EmploymentDate : date, Salary : currency)
1. Provide the relational algebra statement to find the names, fees and emails
of all Campers who attended both the GirlScience and the GirlTech camps
in 2016 (3 marks).
2. Provide the relational algebra statement to find the names of the mentors
who ran the MakerTech Camps for Campers that where older than 10 years
old. Display their names together with the start date and year of the Camps
they attended (3 marks).
3. Provide the relational algebra statement to find the names, t-shirt sizes and
emails of the 7 year old Campers who never attended a Camp that was led
by a Mentor named Sandy who earns a salary of $500.00 (4 marks).
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B. Normal Forms
Consider a Book relation denoted by R with attributes ABCD. A sample instance
of R is shown below:
BookTitle (A) Distributor (B) Topic (C) Price (D)
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Database Design Addison W Databases 115.00
C++ Wiley Programming 119.00
C++ Addison W Programming 129.00
1. This relation may have some data anomalies. Explain what the three anomalies are and give an example of each, using the Book relation (2*3 = 6
marks).
2. Suppose that the following sets of functional dependencies hold over R. For
each one of the following sets of functional dependencies, determine the
highest normal form and motivate your answer (2*3= 6 marks).
(a) C −→ D, C −→ A, B −→ C
(b) A −→ B, BC −→ D, A −→ C
(c) AB −→ C, AB −→ D, C −→ A, D −→ B
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C. Physical database design
Reconsider the following relational schema about Kids (Campers) that register for
Camps in Adventures in Science and Engineering.
Camper(CName : string, Age : string,Email : string, tshirt : string, Fee : real)
Camp(CampID : int, CampTitle : string,EmpID : int, StartDate : date, Year : date)
Signup(CName : string, CampID : string)
Mentor(EmpID : int, Name : string,EmploymentDate : date, Salary : currency)
Suppose that the Camper table is organized as a heap file, and that it contains the
records of a total of 20,000 kids (i.e. current and past Campers). A disk block
has the capacity to store 1,000 records and the buffer pool contains 10 slots. On
average, a Camper registers for two Camps in a year and attends the Camps for
four years in a row.
1. Explain how you would use any one of the two different heap file implementations, as discussed in class, in order to organize the pages of the Camper
table on disk (5 marks).
2. Assume that you wish to execute a query that displays all the personal
information about the Campers in your database (i.e. SELECT * FROM
Camper). Explain the exact process that is followed i) to locate the data
on disk, ii) to transfer the data into the buffer and iii) to deal with potential
buffer sizing issue (8 marks).
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D. Storage and Indexing
Consider the following table that contains the information about the prices (in $)
and ratings of products sold in a convenience store.
ProductID Type Price Rating
120 Gum 1 5
121 Camera 50 2
122 Candy 8 4
123 7Up 24 Box 18 5
124 Kitkat 2 3
125 Coke 24 Box 18 5
126 Nachos 6 4
127 Hat 73 5
128 Jacket 94 5
129 Boots 99 4
130 Backpack 27 3
131 Camera 52 5
132 Walking Stick 58 2
133 Aero 5 4
134 Cheese 14 2
135 Carpet 89 4
Assume that the DBMS constructs a B+ tree with an order d of 2 on the Price
attribute. You decide to store the data entries using Alternative 3.
1. Show the final tree after you have inserted all the data in the order they are
shown in the table. That is, do not use the bulk loading algorithm (5 marks).
2. Suppose that the products with the following ProductIDs are removed from
the tree, in this order: 131, 128, 127 and 129. Show the resultant tree after
you have deleted these four entries (5 marks).
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