Revision

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Revision

• CS-1Q
• IM Lecture 10
• Phil Gray

Simon Gay
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The Class Test

• Friday 31st January, 1.30 - 2.45 pm,Hunter Halls
  (East and West)
• Two questions ANSWER BOTH!
• one question on HCI, of similar structure to
  thepractice questions and past exam questions
• one question on Mathematics and Information
  Management
• 30 minutes per question, 15 minutes
  reading/checking time

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A Word from Chris about HCI

• You need to know what a mental model is.
• Revise the section on Elicitation.

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Overview

• Basic Division between
• Information Management ( 75-80)
• Sets Relations (20-25)

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Types of Questions

• objective content
• what is
• define
• list
• explain the difference between
• worked examples
• e.g., ER diagrams, queries
• questions on sets relations
• critical question
• compare, assess
• explain the relationship between

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Content

• Lecture 1 Issues in Managing Data
• Lecture 2 Data Modelling ER Diagrams
• Lecture 3 The Relational Data Model
• Lecture 4 Creating Database Tables from an ER
  Diagram
• Lectures 5-6 Sets and Relations
• Lecture 7 Querying Relational Databases
• Lectures 8-9 SQL

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Content

• Data, information and knowledge
• Databases DBMSs
• definitions
• layered architecture
• ER Modelling
• whats a model?
• be able to define the elements
• be able to produce a simple ER diagram

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Content

• Relational Model
• be able to define the elements
• keys
• constraints
• transforming from / comparing to ER Model
• Sets Relations
• based around the tutorial exercises

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Content

• Querying Relational Databases
• understand the operations
• be able to relate them to sets relations
• SQL
• know the syntax semantics
• be able to write and explain simple queries

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Model Answer (a)
(3 marks) A database is one or more structured
sets of persistent data, usually held on computer
and associated with software to update and query
the data. A database management system is a suite
of programs that manage databases (or
an information system where the data may be
shared by different applications).
Other functions (1) multiple views of the same
data (1) controlled concurrent access to data (1)
management of security and integrity
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Model Answer (b)
1 mark for entities, 1 mark for attributes, 1
mark for composite attribute, 1 mark for
relationship, 0.5 marks for cardinality, 0.5
marks for total participation of widgets, 1 mark
for primary keys
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Model Answer (b) (continued)
(2 marks) The association should be represented
by including an attribute in the Widget table to
hold a foreign key referring to the primary key
in the Warehouse table.
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Model Answer (c)
(i) (1 mark) True, because ? stands for the empty
set, and the empty set is a subset of every set.
(ii) (1 mark) True, because A is the set of all
elements of U that are greater than 2. The order
of listing elements is not significant.
(iii) (1 mark) 3, 1
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Model Answer (c) (iv)
(2 marks)
Not transitive because, for example, we have
tuples lt1,2gt and lt2,3gt but not lt1,3gt (there are
2 other examples)
Transitive means if xRy and yRz then xRz.