IT-403 Fundamentals of Databases
etrade2016
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( Assignment 1 Deadline: Day 21 / 10 / 2017 @ 23:59 [Total Mark for this Assignment is 5 ] ) ( Fundamentals of Databases IT-403 )
( Instructions: This Assignment must be submitted on Blackboard via the allocated folder. Email submission will not be accepted. You are advised to make your work clear and well presented ; marks may be reduced for poor presentation . You MUST show all your work . Late submission will result in ZERO marks being awarded. The work should be your own, copying from students or other resources will result in ZERO marks. Use Times New Roman font for all your answers. ) ( Student Details: Name: ### CRN : ### ID: ### )
College of Computing and Informatics
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( 1 Mark ) ( Learning Outcome(s): Define and understand useful terms. )Question One
Define and explain the following terms (give examples):
- Domain of an attribute
- Atomic
- Super key
- Candidate key
- Primary key
( 3 Mark ) ( Learning Outcome(s): Define the relational model. )Question Two
Consider the following three relations:
For each of the following relational expressions, compute the result on the above relations and submit only the final answer. For example, for query: πB,D(S), the result should be entered as: {(a, x), (b, y), (b, x), (c, y)}.
a. πA,D(R×S)
b. πA,D(R∞S)
c. πE(T)−πE(S∞T)
( 1 Mark ) ( Learning Outcome(s): Describe different types of relational model keys and their use in databases. )Question Three
Consider the relational database of instructor:
|
ID |
Name |
DOB |
Gender |
Dept_No |
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E101 |
Ahmed |
15-JUL-1986 |
M |
2 |
|
E103 |
Ali |
04-MAY-1989 |
M |
2 |
|
E104 |
Sara |
29-OCT-1987 |
F |
1 |
|
E102 |
Omar |
20-MAY-1988 |
M |
3 |
|
E105 |
Hind |
23-JAN-1980 |
F |
4 |
a. Identify at least four possible superkeys?
b. Identify at least three possible candidate keys?
Relational Algebra
Purpose
The purpose of this assignment is to help you learn more about the relational algebra.
Brief Introduction
Relational Algebra
Relational algebra is a procedural query language, which takes instances of relations as input and yields instances of relations as output. It uses operators to perform queries. An operator can be either unary or binary. They accept relations as their input and yield relations as their output..
Action Items
· You are requested to submit one example of relational algebra .
