Convert COURSE to third normal form.

COURSE(CourseCode, CourseTitle, TeacherID) keeps the teacher identifier as a foreign key. TEACHER(TeacherID, TeacherName) becomes a separate table holding each teacher once.

State the final set of tables for the enrolment example in third normal form.

The four tables are STUDENT(StudentID, StudentName, TutorGroup), COURSE(CourseCode, CourseTitle, TeacherID), TEACHER(TeacherID, TeacherName) and ENROLMENT(StudentID, CourseCode, Grade). Each fact is now stored exactly once.

What redundancy is removed by reaching third normal form here?

A teacher's name is stored once in the TEACHER table instead of once per course. A misspelt teacher name now needs only a single correction.

Eduqas A-Level Computer Science A500QS

Data Structures: Arrays, Records and Hash Tables

Topic overview One-dimensional arrays and indexing Two- and three-dimensional arrays Manipulating arrays: insertion, deletion and searching Records and fields Arrays of records and record manipulation Hash tables, hashing and collisions Choosing and justifying a data structure

Stacks, Queues, Linked Lists and Trees

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Boolean Logic and Simplification

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Algorithms, Pseudo-Code and Programming Constructs

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Variables, Scope, Parameters and Identifiers

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Recursion and Modular Programming

Topic overview Recursion and the base case How recursive calls use the stack Recursive algorithms: factorial and Fibonacci Recursion compared with iteration Integer division with DIV and MOD Standard functions and standard modules User defined subprograms and modular design

Sorting Algorithms

Topic overview Why a variety of sorting algorithms is needed Bubble sort Insertion sort Quicksort Comparisons, exchanges and passes Storage space and sorting efficiency Writing and altering sort algorithms

Searching and Shortest-Path Algorithms

Topic overview Linear search Binary search Comparing linear and binary search Graphs, weights and the shortest-path problem Dijkstra's shortest-path algorithm Tracing a shortest-path algorithm by hand Choosing the right searching technique

Big O Notation and Algorithm Efficiency

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Validation, Verification and Testing

Topic overview Validation and verification compared Types of validation check Implementing validation in an algorithm Verification techniques Validation and verification of data in databases Choosing test data Dry running, trace tables and identifying errors

Data Compression

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Programming Paradigms and Computer Languages

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Systems Analysis, Maintenance and Documentation

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System Design and Human-Computer Interaction

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Software Engineering Tools and Translators

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Computing, Society and the Law

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Computer Architecture, the Processor and Assembly Language

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Input, Output and Secondary Storage

Topic overview Input devices and how data is captured Output devices and how results are presented Choosing input and output devices for a situation Voice input, dictation and voice print recognition Magnetic, optical and solid state storage Comparing secondary storage for a purpose Disc organisation, fragmentation and defragmentation

Networks, Protocols and the Internet

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Data Transmission and Network Performance

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Number Systems and Binary Arithmetic

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Data Types, Characters and Floating Point

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Files, Records and File Organisation

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Databases, Normalisation and Entity Modelling

Topic overview Data consistency, redundancy and independence Relational databases and other database models Primary keys, foreign keys and indexes First normal form Second normal form Third normal form Entity relationship modelling User views and turning data into information

SQL, Big Data and Distributed Systems

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The Operating System and Its Modes

Topic overview The need for an operating system and the role of the kernel Managing peripherals, processes and memory protection The user interface and the layers between user and hardware Directory structures and file attributes Utility software Batch processing, real time control and real time transaction systems Types of operating system: single-user, multi-user, multi-tasking and multi-programming Designing an interface for different users and environments

Interrupts, Memory Management and Scheduling

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Types of Software System

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Data Security, Cryptography and Attack

Topic overview Online updating and the integrity of shared files Dangers of holding personal data Clerical procedures, access levels, passwords and write protection Cryptography: its purpose, and symmetric and asymmetric keys Hashing, digital signatures and certificates Caesar and Vernam ciphers and comparing cipher strength Biometric technologies and their limitations Threats, damage and contingency planning Malicious software, hacking and penetration testing

Databases, Normalisation and Entity Modelling

Third normal form

3 things to know
Component 2

Overview

Rule for third normal form and transitive dependency.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

State the rule for third normal form.

Key term

What is a transitive dependency?

Key term

Identify the transitive dependency in COURSE(CourseCode, CourseTitle, TeacherID, TeacherName).

Questions from this subtopic

Each one with the model answer underneath.

1
State the rule for third normal form.
Model answer
A table is in third normal form when it is in second normal form and has no transitive dependencies. Every non-key attribute must depend on the key alone.
2
What is a transitive dependency?
Model answer
A transitive dependency exists when a non-key attribute depends on another non-key attribute. TeacherName depending on TeacherID is a transitive dependency in the COURSE table.
3
Identify the transitive dependency in COURSE(CourseCode, CourseTitle, TeacherID, TeacherName).
Model answer
CourseCode determines TeacherID, and TeacherID in turn determines TeacherName. TeacherName therefore depends on the key only through another non-key attribute.
4
Convert COURSE to third normal form.
Model answer
COURSE(CourseCode, CourseTitle, TeacherID) keeps the teacher identifier as a foreign key. TEACHER(TeacherID, TeacherName) becomes a separate table holding each teacher once.
5
State the final set of tables for the enrolment example in third normal form.
Model answer
The four tables are STUDENT(StudentID, StudentName, TutorGroup), COURSE(CourseCode, CourseTitle, TeacherID), TEACHER(TeacherID, TeacherName) and ENROLMENT(StudentID, CourseCode, Grade). Each fact is now stored exactly once.
6
What redundancy is removed by reaching third normal form here?
Model answer
A teacher's name is stored once in the TEACHER table instead of once per course. A misspelt teacher name now needs only a single correction.

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