Tuesday, 24 November 2009

Zoho Creater Tool

It is easy to implement a data model by using Zoho Creater Tool because the user clicks on create new application and enters the application and form names. The user then selects the time zone that they are in, and then creates a new application. The user then drags and drops the fields that they are going to be using within the data model.

Monday, 23 November 2009

normalisation

5 steps for normalisation:

1) List the un-normalised data and identify repeating groups (in brackets).
2) Choose a key for the main group.
3) Extract the repeating group and give that a key.
4) Identify and extract partial key dependencies.
5) Identify and extract non key dependencies.

For the 0NF i am going to list the un-normalised data.

0NF:

Order

Customer No
Name
Address
Date
Salesman No
Salesman Name
(Item No)
(Description)
(Quantity)
(Price)

Order Value

1NF:

Order

Customer No
Date
Name
Address
Salesman No
Salesman Name
Order Value

Order Item

Customer No
Date
Item No
Description
Quality
Price


2NF:

Order

Customer No
Date
Salesman No
Salesman Name
Order Value

Customer

Customer No
Name
Address

Order item

Customer No
Date
Item No
Quantity

Item

Item No
Description
Price

3NF:

Order

Customer No
Date
Salesman No
Order Value

Salesman

Salesman No
Salesman name

Customer

Customer No
Name
Address



Item

Customer No
Date
Item No
Quantity
Item No
Description
Price

Examples of normalisation and entity relationships


Normalisation

http://www.sqa.org.uk/e-learning/MDBS01CD/page_26.htm

http://sandbox.mc.edu/~gwiggins/syllabi/csc415/normalization-examples.html

Entity Relationship Diagram

http://www.smartdraw.com/resources/tutorials/Entity-Relationship-Diagrams

http://www.umsl.edu/~sauterv/analysis/er/er_intro.html

http://www.cs.sfu.ca/CC/354/zaiane/material/notes/Chapter2/node8.html

Tuesday, 17 November 2009

Rapid Application Development

1) Less Documentation.
2) Faster Delivary Time.

Iterative Builds

1) Phased: Customers uses version 1,2 etc.
2)Prototyping: Customer views version 1.

Iterative Design:

3) Throwaway Prototyping: Design version only.

Prioritising Requirements:

Two Functions:

1) Version release to customer as early as possible.
2) If expectations are high but budgets are low-product must contain the essential elements.

Difficulties:

1) Customers want everything in version 1.
2) For customers to set priorities.
3) Functionality is interlinked and hard to be seperated.

Sample Requirments Scales:

High Priority: Product not acceptable without this function or feature.
mission critical.
required for next release.

Medium Priority: Supports necessary system operations. Required eventually but not immediately.
Would enhance the product.

Low Priority:Nice to have if budget allows.

Steps:

1) List all the features/functions contained in the requirements.
2) Assocaiate each one with a priority category and state a reason why.
3) Sort the list into a descending order of importance.
4) Agree final list with customers.
5)Group features/functions in to versions.

Tuesday, 10 November 2009

RAD

Planning/Analysis/Design/Implementation
Phases-Steps-Technique-Deliverable

Phased Development: Planning and Analysis. For system version 1 analysis, design and implement, then for version two analysis, design and implement, while the user is using version 2,version 3 will be created. system version 3 includes analysis, design and implementation.
Prototyping: This involves planning, then analysis, design and implementation are carried out at the same time in order to get system prototype. the system protype then needs implementating for the final system.
Throwaway Prototyping: This involves planning and analyis, then analyis, design and implementation is carried out at the same time. then design prototype. The final design is created and then implemented in to the system.

Tuesday, 20 October 2009

Data Modelling

The four principles of entity relationshops are:
1) Identification of entities
2) Construction of a process independant of the stored data requirements.
3)Construction of a rebust data model.
4) The construction of a logical model of the data.

The six steps in creating a good entity relationship diagram:

1) Identify data object (entities).
2) List the attributes.
3) Data in logical groups.
4) Identify Primary Keys.
5) Eliminate redundancy
6) Investigate and record relationships.

Tuesday, 6 October 2009

Football

I am a Middlesbrough fan, i enjoy going to as many games as I can. My favourite players are Adam Johnson and David Wheater. I also like following the football scores on television and radio.