Tutorial 1

• Before the Tutorial
• Questions
  • Complete the Sentence
  • Complete the Truth Table
  • True/False

Before the Tutorial

Revise the material from Lecture 01 and Lecture 02.

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Questions

True/False

State whether each of the following statements/propositions is True or False.

1. All databases are relational.

2. The relational model was first introduced by Ted Codd of IBM Research in a classic paper "A Relational Model of Data for Large Shared Data Banks".

3. A relation is physically represented as a table.

4. {d, i, l, m, o, m} is a set.

5. {r, a, t, b, e, r, t}  is a bag.

6. {a, b, c} is equal to {b, a, c}.

7. {a, b, c} is equal to {A, B, C}.

8. The empty set is represented by { } or Ø.

9. The empty set should not be represented by {Ø}.

10. The proper subsets of {x, y} are {x} and {y}.

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Complete the Sentence

Complete each of the sentences below.

The length of the line in the sentences is constant and does not necessarily indicate the length of the answer to be supplied.

1. One organisation which stores information about me on a database is ________________________.

2. The relational model has its theoretical basis in ________________________ theory and first-order predicate ________________________.

3. The number of attributes in a relation is called its ________________________.

4. The number of tuples in a relation is called its ________________________.

5. Each tuple is distinct; there are no ________________________ tuples.

6. The order of tuples has no ________________________ significance.

7. All information in a relational database is represented explicitly at the logical level and in exactly one way - by values in a ________________________.

8. The totality of objects of interest is called the ________________________ set, which is denoted by U.

9. The objects in a set are called the ________________________ of the set.

10. The ________________________ set is a subset of every set.

11. The subsets of S {a, b} are ________________________.

12. If a set contains 4 elements, the set has ________________________ subsets.

13. If a set contains 5 elements, the set has ________________________ proper subsets.

14. If A equals B, then A is a subset of B and B is a subset of ________________________.

15. The ________________________ of A is the set of all elements x in U such that x is not in A.

16. The ________________________ of B minus A is the set of all elements x in U such that x is in B and x is not in A.

17. The ________________________ of A and B is the set of all elements x in U such that x is in A and x is in B.

18. The ________________________ of A and B is the set of all elements x in U such that x is in A or x is in B.

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Complete the Truth Table

Complete each of the following truth tables.

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