1. Section 11 : Normalisation
And Franchise Colleges
11 NORMALISATION
By MANSHA NAWAZ
Section 11 : Normalisation

2. Section 11 : Normalisation
SAD Overview
Systems development undertaken by using Case Tools
used early in development life cycle
Provide requirements and design in terms of Systems Model and Data Model
Case Tools for Systems Modelling:
Dataflow Diagrams (DFD)
Data Dictionary (DD)
Case Tools for Data Modelling:
Normalisation (NF)
A rules based technique undertaken to produce the data model for a system
Entity Relationship Model (ER)
A diagrammatic based technique undertaken to produce the data model for a system
Data Model
Can be implemented on a DBMS such as MS SQL Server, MS Access, etc
Consists of logical and physical view of the proposed systems data.
Section 11 : Normalisation

3. Section 11 : Normalisation
DFD
DDS
Normalised
Tables
E-R Model
DBMS
PHYSICAL VIEW OF DATA
TABLES
LOGICAL VIEW OF DATA
FORMS
Section 11 : Normalisation

4. DBMS NF DATAFLOW DIAGRAMS DataStores, DataFlows and Data Dictionary
DATA MODEL
TABLE SET NF
E-R Model
DBMS
PHYSICAL VIEW OF DATA
TABLES
LOGICAL VIEW OF DATA
FORMS
Database connectivity via websites
www .net technology
Macromedia Dreamweaver
MS Visual Studio
Database connectivity via desktop DBMS such as
MS Access
Database connectivity via programming languages such as MS Visual Basic
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Area of Interest

5. Systems Analysis and Design
DFDs
can provides the base for database development
Used to derive our data model
Datastores
Decompose into a number of related tables
provide the TABLE views for the database
Physical View of data (Internal Schema)
Datastores & Dataflows
provide the FORM views
Logical View of data (External Schema)
Process
reports, queries, functions & procedures
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6. Section 11 : Normalisation
Data Model
Also referred to as Conceptual Model
A Data Model is the representation of a proposed systems database requirements
Data Model provides
a full set of related tables and data
Able to derive physical views (internal schema) of data
Able to derive logical views (external schema) of data
Data Model produced by Case Tools techniques of Normalisation and/or Entity Relationship Modelling.
Proposed processes that operate on the data and/or produce data (process view)
Making sure these tally (event/transaction view?)
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7. Section 11 : Normalisation
Logical View - for User
External Schema View
Form or Screen views provided to the end user.
Datastore & Dataflows represent as logical views in Data Dictionary
Contained in Data Dictionary - Structure and Element view
Physical View - for Designers
Internal Schema View
database structure view that a DBMS requires.
in terms of Tables, Attributes (data fields) and Types (data defn.)
linkage between tables via primary and foreign keys
Datastore decomposed to a set of normalised tables
Normalised datastore represent physical view
Normalisation
takes the logical view and produces the physical view
Take the datastore and produce the tables
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8. Normalisation (NF). Entity Relationship Modelling (ERM).
Provide us with a Bottom Up approach to producing the database tables
Technique covered in other modules
Entity Relationship Modelling (ERM).
Covered in HSQ Databases & SQL Module
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9. Section 11 : Normalisation
Logical View - for User
Form or Screen views provided to the end user.
Datastore structure and element view
Physical View - for Designers
database structure view that a DBMS requires.
in terms of Tables, Attributes (data fields) and Types (data defn.)
linkage between tables via primary and foreign keys
Datastore decomposed to a set of normalised tables
Normalisation takes the logical view and produces the physical view
Take the datastore and produce the tables
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10. Section 11 : Normalisation
Normalisation Rules
0NF Zero Normal Form or Unnormalised data
Data Dictionary Structure and Elements of a datastore
List datastore data: identify key(s) and repeating group of data
represents the logical form view of a datastore
1NF first Normal Form or first normalised data
Remove repeating group(s) to new table(s)
2NF second Normal Form or second normalised data
Remove partial key dependency data to new table(s)
3NF third Normal Form or third normalised data
Remove non key dependency data to new table(s)
represents the physical tables view of a datastore
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11. Normalisation Rational
The normalisation process also ensures
there must be no repeating groups of data in a table
all attributes in a table must be atomic
cannot be broken down into any smaller components
all primary keys must remain unique
every foreign key must have a matching primary key in its related table.
Normalisation is a process that reduces errors due to badly designed data structures (entities, attributes, and relationships).
Normalisation can be carried out at various levels of complexity.
You will need to understand the purpose of normalisation and the methods used to normalise each datastore
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12. Section 11 : Normalisation
Summary
Rules to assist in the creation of a DATA MODEL
A step by step technique which restructures the data of a system into a more efficient and desirable form.
Takes logical datastore view to physical table view
Makes improvements in terms of :
NO DUPLICATION
NO REDUNDANT
NO NULL
REDUCTION IN PHYSICAL SIZE
QUICKER INFORMATION RETRIVAL
LEADS TO A FULLY OPTIMISED SET OF TABLES
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13. Document : Design Specification
Data Dictionary lecture 08
Data Stores - Structures & Elements lecture 08
Data Flow - Structures & Elements lecture 08
Data Stores and Flow Usage lecture 09
Process Descriptions lecture 10
NORMALISATION lecture 11
Database Tables derived from Data Store Descriptions
ONF - Logical View of Datastores
1NF
2NF
3NF - Physical View of Tables
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14. Further Reading Why Normalisation or ER Modelling? www Online Tutorial
Supplement Notes on
Why Normalisation or ER Modelling?
www Online Tutorial
Normalisation
NORMALISATION
- Worked Example -
- Problems -
-  Answers  -
> Normalisation Video
Section 11 : Normalisation