HND Database Design Concepts Assignment

DATABASE DESIGN CONCEPTS ASSIGNMENT

Part 1

Question 1

The internal schema describes how the data will be physically stored and accessed, using the facilities provided by a particular DBMS. For example, the data might be organized so that all the insurance policies belonging to a given customer were stored close together, allowing them all to be retrieved into the computer memory in a single operation. The internal level is like a space where data are floating in the space e.g pool of data. The internal level is still the logical view.

The conceptual schema (sometimes called the logical schema) describes the stored data in terms of the data model of the DBMS. In a relational DBMS, the conceptual schema describes all relations that are stored in the database. Table definition or data definition are been used here e.g the create table and drop table.

The external schemas specify views that enable different users of the data to see it in different ways. As a simple example, some users of policy data might not require details of the commission paid. By providing them with a view that excludes the Commission Rate column, we would not only shield them from unwanted (and perhaps unauthorized) information, but also insulate them from changes that might be made to the format of that data. . Data manipulation is use to create SQL in a programming language e.g. SELECT. SQL have three languages, which are data manipulation, data definition and data management like granting, revoking, creating index.

The advantages of the three-tiered architecture are division into levels allows both developers and users to work on their own levels. They do not need to know the details and changes in the other levels. Meaning each level has its own independence. This three-schema helps us to provide data security of data’s among different users accessing the database, ensures data integrity and avoid duplication of data’s in the database. It helps us to establish and maintain relationship among the data’s in the database.

Part 1

Question 2

Logical independence arises in a database when application programs are written on external levels. We can change the conceptual level by adding columns to tables or by adding tables to the database and no application code needs to be re-written.

Data independence is the capacity to change the schema at one level of a database system without having to change the schema at the next higher level. If the schema at one level is changed, and the mappings to the next higher level are changed, the schema at the next level can remain unchanged. And there are two types of data independence namely logical data independence and physical data independence.

Logical data independence is the capacity to change the conceptual schema without having to change the external schemas or application programs. Only the view definition and the mappings need to be changed in the DBMS that supports logical data independence.

Physical data independence is the capacity to change the internal schema without having to change the external schemas.

Data independence is accomplished because, when the schema is changed at one level the schema at the next higher-level remains unchanged only the mapping between the two levels is changed. 

Part 1

Question 3

Database is an integrated collection of data organized to meet the needs of one or more users. Databases are used today in commercial and non- commercial environment.

Commercial Environment	Non- commercial Environment
Banks	Government Bodies
NHS-Hospitals	Libraries
Educational Sectors	Churches and Religious Organizations
Telecom Sector	Home Office
Web Industries	Security Industry
DVLA/TV Licenses	Charity Organizations
Aviation Industry

Banks- use database to keep information about customers and their accounts. All customer details like name, address, phone numbers, date of birth etc are recorded in the bank database when customers open an account in the bank. This record will be kept in the database and can be updated anytime there is a change in details.

NHS- holds a very huge database of all patients. Each time you visit your GP, he/she call up your details on the database. All NHS work are really done on computer using database. E.g. transplanting, radiology etc.

Educational sector- University, colleges and other learning institutions store student and staff information on their database and can be updated if their details changes.

Airline- The aviation industry uses databases to also store details of customers, reservation systems for booking airline flights and other travel arrangement. It is also a huge database that can be seen and use all over the world. You can access the database anywhere to book or cancel your reservations.

DVLA/TV licenses- DVLA and TV Licences store customer information on their database to use whenever they need for licensing systems such as drivers and vehicles, and to keep track of all people been given licences. TV licences on the other hand uses database to also store information about everyone that purchases TV in this country and keep a record of update.

Home Office- In non-commercial environment like home office, people’s details are kept in a huge database. These details are used when processing applications and other issues. Although home office database are very huge because they handle almost everybody details in this country plus the EU database. These entire databases are link to many other organizations especially if the governments want to track down someone records. 

SIA (security industry authority) also store customers and staff information in their database and retrieve to use at anytime. They uses it for application processing and granting of licence etc.

Library- libraries hold information of everyone that uses their library in their database. E.g inventory systems raging from the books held in a library

Other Government offices- like Inland Revenue and NIC also hold large amount of details of information of people on their database. For example, before you work in this country, you must apply for a national insurance number and your details will be saved on their database so also Inland Revenue that look into taxes of everyone.

Churches keep their members information in their databases. That information could be used to send personal emails or general updating purposes through emailing.

Part 2

Question 1

1St Normal Form

Customer Table Customer Number Customer Name Customer Address	Order Table Order Number Order Date Required Date
Department Table Department Code Department Name Department Rate Job Number Job Duration

Above is a 1st Normal Form: Primary and Foreign Keys appear

2nd Normal Form

Customer Table Customer Number Customer Name Customer Address	Order Table Order Number Order Date Required Date
Department Table Department Code Department Name Department Rate	Job Table Job Number Job Duration

Above is a 1st Normal Form: Some parts of tables repeat themselves

3rd Normal Form

Customer Table Customer Number Customer Name Customer Address	Order Table Order Number Order Date Required Date Customer Number FK
Department Table Department Code Department Name Department Rate	Job Table Job Number Order Number FK Department Code FK Job Duration
Job Cost Table Job Cost Number PK Cost Number FK Order Number FK Job Number FK Department Code FK Invoice Number FK	Invoice Table Invoice Number Order Number Invoice Date

ERD

HND Computer Platforms Assignment

Computer Platforms Assignment

Question 1

Assess and make a record of the computer specifications, especially of the model and speed of the main processor, RAM memory modules and motherboard. Research and find out the specs of the motherboard in the function of extensibility and RAM capacity.

Evaluate the performance of the computer system and suitability for the use in a class room.

Answer

The computer system I would like to evaluate is a sleek and sophisticatedly designed space-saving Packard Bell OneTwo M D6020uk All-in-one PC (desktop computer) featured with the brilliant new Windows® 7 Home Premium OS as it is shown in the picture on the left.

Microprocessor
Type	Intel Pentium Dual-Core T4300 processor
L2 Cache	2MB
RAM Memory Clock Speed	800MHz FSB
Processor Clock Speed	2.1GHz
Chipset	Intel Graphics Media Accelerator 4500 M
Screen
Screen resolution	1600x900
Screen Size	20’’ inch
Technology and ratio	TOUCH PANEL - 1000:1 (Contrast ratio)
Sound
	Integrated on motherboard or on PCI Slot
Speakers	Stereo speakers
Memory
RAM	3GB DDR2 memory
RAM Memory Clock Speed	800MHz FSB
Hard Drive
Hard Drive	640GB Hard Drive
HDD rotation speed	7200rpm SATA
Operating System
Operating System	Genuine Windows® 7 Home Premium
Operating System mode	64-bit
Monitor
Monitor	20’’ Touch screen monitor
Peripherals
	Integrated Graphics
	DVD Rewriter
	Digital TV Tuner
	Built-in wireless (802.11b/g/n)
Multimedia card reader	5 in 1 (xD,SD,SD HC,MS,MS pro,MMC)
Optical drive	TRAY SUPER MULTI DVDRW

The above mentioned PC is suitable for all the applications the Postgraduate Students could possibly use. 3GB RAM is more than sufficient enough to use applications like Photoshop, Dreamweaver or MS Project Visio. All these mentioned applications are the main applications which require a lot of memory, especially if they are used for web designing and developing purposes.

Question 2

Discus features of varies types of operating system in a view of the performances required by Postgraduate students. Propose basic customization for chosen operating system.

Answer

An operating system, or OS, is a software program that enables the computer hardware to communicate and operate with the computer software. Without a computer operating system, a computer would be useless. It works as an interpreter between the software and the hardware. It also controls the way the system performs.

A Computer System we need to customize and use for the Postgraduate students will require a lot of RAM memory. For that reason we need to replace and enhance the RAM. Applications like Photoshop and Dreamweaver require lots of memory space while they are running.  RAM Memory Clock Speed is also important as it represents the information transferred in a second between North and South Bridges of the Processor. Processor speed also needs to be fast for the above mentioned applications; otherwise the PC will freeze and cannot operate properly.

Operating Systems are generally categorized into four types. They are explained below:

1.       RTOS (Real-Time Operating System):

A real-time operating system (RTOS) is a multitasking operating system intended for real-time applications. Such applications include embedded systems (programmable thermostats, household appliance controllers), industrial robots, spacecraft, industrial control and scientific research equipment. The main object of real-time operating systems is their quick and predictable response to events. Some of the examples of the RTOS are VxWorks, QNX, RTLinux, etc.

2.       Single User, Single Tasking Operating Systems:

As the name implies, this operating system is designed to manage the computer so that one user can effectively do one thing at a time. The Palm OS for Palm handheld computers is a good example of a modern single-user, single-task operating system. This kind of operating system provides access to the system to single user at a time. If another user needs access to the computer, they must wait till the current user finishes what they are doing and leave.

3.       Single User, Multi Tasking:

As the name goes in this kind of OS a single user can perform multi tasks together at a time. Multitasking can be of two types namely preemptive and cooperative. In the former one the system slices the CPU time and dedicates one slot to each of the programs and in the latter one multitasking is achieved by relying on each process to give time to the other processes in a defined manner. The examples are:

Multi-tasking (co-operative), single user - Windows 3.1, Mac OS 9.

Multi-tasking (preemptive), single user - Windows 95/98/ME.

4.       Multi User, Multi Tasking:

This kind of OS enables multi users to work multiple tasks at the same time. Which means different users can take the advantage of the computer resource simultaneously and for this normally a network is used and established and the users use the remote terminal. Some of the examples are UNIX, VMS, Mainframe, etc.

As per the need of the post-graduate students, single user multi tasking OS will be the best option. In this OS we can use Windows XP which is already available on the system. This operating system supports mostly all the applications which are required by the given students.

Question 3

Propose key components that have to be changed in order to suit needs of the above specified users. If you find it cheaper and suitable you can also specify completely new system. For the new proposed system produce a security policy.

Answer

A Computer System we need to customize and use for the Postgraduate students will require a lot of RAM memory. For that reason we need to replace and enhance the RAM. Applications like Photoshop and Dreamweaver require lots of memory space while they are running.  RAM Memory Clock Speed (it is 800MHz FSB in our system) is also important as it represents the information transferred in per second between North and South Bridges of the Processor. Processor speed also needs to be fast for the above mentioned applications; otherwise the PC will freeze and cannot operate properly.

For this purpose, I would suggest to enhance:

1.    RAM memory (3GB DDR2 in our system)

2.    RAM memory Clock Speed (800MHz FSB)

3.       Processor Clock Speed (2.1GHz in our system)

Security Policy:

A computer security policy defines the goals and elements of an organization's computer systems. It is a document that outlines the rules, laws and practices for computer network access. This document regulates how an organization will manage, protect and distribute its sensitive information. The security policy required for the current system should be similar to the following some points:

·         The user will not be allowed to download anything without the permission of the administrator.

·         The user will not be able to customize the desktop or any other part of the system.

·         The user should keep changing his password in regular intervals.

·         The user will not be allowed to visit porn sites.

·         The user will not be having the complete access of the system, as in, he can just use the applications and My Documents folder for saving his work.

·         The user will not have access to the Control Panel and the Run window of the start menu.

·         There should be a planned regular schedule for data backup.

·         The user will not be allowed to visit illegal and illegitimate websites.

·         The user should seek permission of the administrator before using the system and turn off the system when he has finished using the system.

·         The user will not be allowed to delete or modify the documents, files, folders, etc not belonging to him.

Question 4

Produce a hardware and software test plan for the system after those changes. Include health and safety plan.

Answer

Before we make any changes we need to check the RAM memory slots on a motherboard if there is any available slot for the new RAM. If there is no other slot available, then we need to take out the existing one and replace with a new and better one. Then we need to make sure that our motherboard supports better RAMs (for example DDR3 upgrade).

Hardware Test Plan:

1.    Replace the new RAM with an existing one.

2.    Switch on the computer.

3.    Check if an Operating System boots properly and the programs run smoothly.

4.    If all the conditions above work, then we can say the test was successful.

Software Test Plan:

1.    Open RAM-hungry applications like Photoshop and Dreamweaver.

2.    Try to work on the Photoshop and write a code on Dreamweaver and at the same time to try upload some information on internet using Dreamweaver’s own FTP program.

3.    If the system works smoothly without crashing, then we can say that the test was successful.

Health and Safety Test Plan:

·         Any kind of food or drink in any form should not be allowed.

·         There should not be any live or open wires.

·         Proper care must be taken while working with the electric switches.

·         The system should not be directly exposed to excessive heat or smoke.

·         Do take extra care and proper guidance if you need to work with any hardware or the electric parts of the system.

·         All the cables should unplugged before opening the cabinet of the CPU.

·         The user should not work continuously in front of the screen or on the keyboard and breaks at regular intervals are recommended.

Question 5

Produce user documentation for the new system.

Answer

1.    Go to Start > My Computer > Right Click the mouse button.

2.    Click on Properties.

3.    You will see all the details of your computer.

4.    You should be able to see the system specifications of your computer.

References:

·         http://www.wikipedia.org

·         http://www.books.google.com

·         http://www.packardbell.co.uk

·         http://www.computers-guru.blogspot.com

·         And my personal knowledge about Computer Systems.