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Information Processing Technology Core 2: Information Systems and Databases

Information systems: Information systems perform a set of information processes requiring participants,

data/information and IT.

Created to provide access to information for an organisation or individual.

Data is head in a database and access is achieved using a DBMS.

Characteristics of information systems:

− Organisation of data into information.

− Analysing the information to give knowledge.

Purpose of information systems:

Transaction processing systems [TPSs]

Collect, store, modify and retrieve the daily transactions of an organisation.

− Batch processing collects the transaction data and processes it later.

− Real-time processing is processed immediately.

Examples: POS terminal, processing credit card payments, tracking receipts of

materials from suppliers.

Decision support systems [DSSs]

Assist people to make decisions by providing information, models and analysis

tools.

Examples: system that analyses the stock market and helps the user to make

decisions about buying and selling shares.

Expert systems

Provide information and solve problems that would otherwise require a person

experienced in that field. It asks a number of questions and compares their answers

to a knowledge base

Examples: system that help doctors diagnose infectious blood diseases and

prescribe antibiotics. Patient’s medical details are compared to its knowledge base.

Solutions are not always correct, up to the user to accept or reject solution.

Management information systems [MISs]

Provide information for the organisation’s managers. Presents basic facts about the

performance of the organisation.

Examples: Execute Information Systems (EIS) provides information on strategic

issues.

Office automation systems

Provide people with effective ways to complete administrative tasks in an

organisation. Uses a range of software and communication technology.

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Examples of database information systems Information systems that uses a database. Databases are accessed by a database

management system [DBMS].

• School database: information about teachers, students, classrooms and subjects.

• RTA: information on automobiles. • Video stores: information on borrowers and videos



School Database

En

viro

nmen

t − The school community (students, staff, parents)

− The educational services offered by the school/

− The flow of information between the school and authorities.

− The hardware and software.

− Any organisation, business or individual that receives information generated by the

school database administration systems or supplies data for the system.

Purp

ose

− To maintain the efficient operation of the school, its personnel, fiancés, resources and

administrative tasks.

− To provide information on student enrolments, subject selections and assessments for

both school staff and educational authorities.

Dat

a / i

nfor

mat

ion

Information on people, resources and processes eg…

− Equipment register.

− Finance and purchase orders.

− GST records.

− Library resources and loans.

− Staff information.

− Student marks and grades.

− Student personal and academic information.

− Timetables and room allocations.

Most data stored on an administration computer network in the school office and library and

some on individual staffroom computers.

Part

icip

ants

− School office and library staff who use the system.

− Teachers who add class information into the system.

− Students who search the library catalogue.

− Everyone in the school is likely to be a system participant at some stage.

Info

rmat

ion

Proc

esse

s

C O

A S

P T

D

− Collecting: through enrolment forms, marking of class rolls, payment of fess, recording

results in class mark books, library loans and returns and administrative tasks.

− Organising and storing: a number of different databases that deal with student and

staff information, resources of various types and finances.

− Analysing and processing: creating class lists, student reports, financial reports,

purchase orders, receipts and over due book lists.

− Transmitting and receiving: some data are transmitted to and received from

educational authorities eg BOS.

− Displaying: input and output data are displayed on VDUs and printouts.

Info

rmat

ion

Tech

nolo

gy − Computers (data entry, access and in staffrooms)

− Barcodes readers (library loans and returns).

− A student inquiry and loan/circulation network.

− Software: OASIS office network administration system, motorised mark book,

spreadsheet application.



Context diagram

Student and staff information

Purchase orders

Receipts

Financial reports

Marks and grades

New equipment data

Purchase requests

Sales and charges

Timetable data

Class notes

Student / staff data



RTA Vehicle and Driver Information Database

En

viro

nmen

t − All drivers, driving instructors, driver examiners.

− Vehicle owners, vehicle inspectors.

− RTA services eg registration and licensing.

− Flow of information between the RTA and the NSW Department of Transport.

− Police and courts

− Hardware and software.

Purp

ose

− To manage the registration all the drivers and motor vehicles in NSW.

− To send out vehicle registration payments requests.

− To provide statistical information on drivers and vehicles to the government and

registration information to other authorities.

Dat

a / i

nfor

mat

ion

− Driver personal details, payment details.

− Driver licence number, license type and classification, driving history.

− Vehicle identification number, make and model.

− Vehicle owner details, registration number, payment details.

− Vehicle inspection record, insurance details.

− GST records. All available to authorise RTA employees at any motor registry and vehicle inspection station

anywhere in the state.

Part

icip

ants

− Data entry operators, inspectors, counter staff and administration officers at RTA offices.

− Motor registries and motor vehicle inspection stations.

− Police Department Traffic Branch.

Info

rmat

ion

Proc

esse

s

C O

A S

P T

D

− Collecting: through registration application forms, licence applications, renewals, vehicle

inspection and driving test results.

− Organising and storing: a number of different databases that deal with drivers, vehicle

information and finances.

− Analysing: producing statistics on registered vehicles and licensed drivers.

− Processing: vehicle registration and licence renewal forms are sent out.

− Transmitting and receiving: data on vehicles and drivers are transmitted to the Police

and other authorities when requires.


Info

rmat

ion

Tech

nolo

gy − Computers – keyboards and monitors (data entry and display terminals)

− EFTPOS machines (credit / debit card payments)

− Barcode scanners (registration notice payments).

− Networking between the computers (in office / building and links to a state WAN)



Context diagram

Renewal notices

Statistical reports

Driver and vehicle details

Financial reports

Licences and registrations

Fees, charges

Licence and registration data

Inspection reports



Video Store Information Database

En

viro

nmen

t − Customers and staff

− Suppliers

− Entertainment and other services supplied by the store.

− The flow of information between the store and its head office.

− Hardware and software.

Purp

ose − To keep accurate records of the stock (rental and sales).

− To collect data for further analysis by store management.

Dat

a / i

nfor

mat

ion

− Customer details (current loans and overdue items).

− Video rental title records (items in stock and on loan)

− Saleable items records (videos, snack foods).

− Rental and/or sale figures for each item.

− GST records. Most available to store staff, some may be available to customers through inquiry terminals.

Part

icip

ants

− Staff who check out videos and other products

− Staff who process returns.

− Staff who authorise orders for new stock.

− Head managers who use the data provided by the system for inclusion management and

planning reports.

Info

rmat

ion

Proc

esse

s

C O

A S

P T

D

− Collecting: through membership applications, sale items and rental videos passed over

the scanner, and new products that arrive at the store.

− Organising and storing: in product and customer databases.

− Analysing: producing statistics on video rentals, sales, delinquency rates (non-return of

videos) and store income.

− Processing: products are sold, rented, returned or arrive as new products. Video rental

or return, customer’s record is updated.

− Transmitting and receiving: all data is transmitted to the head office.


Info

rmat

ion

Tech

nolo

gy

− Computers – keyboards and monitors (enter details of a new rental customer)

− Barcode scanners (database input devices).

− WAN link from the head office (to update database when there’s new video rental titles).

− Customer inquiry terminals – touch screen and web like interfaces.

− Database management and sakes software.

− Network communication software.



Context Diagram

Stock write-offs

Rental and sales statistics

Financial reports

Loans and overdue reports

Rental returns

New stock

New members

Rental and sale data



Organisation methods Process of arranging, representing and formatting data.

Database: an organised collection of data.

Non-Computer Methods:

− Telephone book

− Dictionary

− Recipe book

May be sorted:

− Alphabetically

− Numerically

− Chronologically

− By Category

Computer-based Methods:

− Flat-file systems

− Database management systems

− Hypermedia

Non-computer and computer-based methods: Computer based methods Non-computer based methods

− Easily edited.

− Large storage.

− Fast retrieval.

− Display options.

− Easily searched through.

− Many people can access it at once.

− Backup storage can be easily kept.

− Access to data can be restricted

− Sorting of data is flexible over a range of

fields

− Convenient to obtain information.

− Easily, inexpensively organise data.

− Do not need a computer or computer skills.

− Easier to keep secure therefore, remain more

private.

− Data is more difficult to use for other

purposes.



Which system to use?

Computer-based systems Information task

Manual system Flat file DBMS Relations DBMS Hypermedia

Appointments diary

Ideal for personal

use ⇒ high

probability and

accessibility.

Ideal for business

use (tracking more

than one person)

⇒ easy

maintenance.

Too complex for

task.

Ideal for travellers

who have access

through the Web.

Store sales or product catalogue

Ideal for letterbox

drops, handouts,

etc.

Ideal for simple

lists only.

Suitable but

generally too

complex for task.

Ideal for access via

the Web and e-

commerce.

Stock / inventory

Too slow and

difficult to maintain.

Ideal for simple

lists only

Ideal for larger and

more complex lists.

Generally not

suitable for the

task.

Personnel records

Too slow and

difficult to maintain.

Ideal for simple

lists only

Ideal for larger and

more complex lists.

Generally not

suitable for the

task ⇒ poor

security and

privacy.

Phone and address list

Ideal for personal

use ⇒ high

portability and

accessibility.

Ideal for larger lists

or business use ⇒

easy maintenance.

Suitable but

generally too

complex for the

task.

Ideal for access via

the Web.



Databases Database: a large storage of information. As an information system, a database allows the

effective manipulation of information it contains through a Data Management System (DBMS).

Data Structure of a Database:

File A block of data. A file in a database is divided into a set of related records.

Record Collection of facts about one specific entry in a database. A record is divided into one or

more related fields.

Field Specific category of data in a database. Data items in a field are made up of characters.

Character Smallest unit of data people can use eg letters, numbers and special symbols.

Keys

Fields that are used to sort and retrieve information. Usually, each key holds a unique

item that applies to only one record. Key is used when records are sorted, not all data

has to be read or retrieved.

− Single key: fields in which each item of data is unique.

− Composite/compound key: made by joining two or more fields together. Used

when no data item in any field can be guaranteed to be unique.

− Primary key: a single or compound key that must have a value, cannot be empty.

− Secondary key: a field that contains useful items of data often used in searches,

not always unique.

Type

s of

key

s

− Foreign key: an attribute of a table that is a primary key of another table.

Flat-file databases: Organises data into a single table.

- Simple to create and organize

- Inexpensive

- Data for the whole database is contained in a single file

- Managed by programs called file managers

- Consists of fields, records and files

- High level of data redundancy

- Access is often sequential, slower access

Relational databases: Organises data using a series of related tables.

- Provide a method of storing data based on multiple databases linked together by

common keys. The keys provide the facility to build up huge databases without necessary

duplicating information (data redundancy) – the data is shared.

- Draws information from one or more additional files as well as the current file

- Needs a Primary Key / Link (Unique key field)

- Organisation of data involves a schema.



Relationships are built between the tables of the relational database to provide a flexible way

of manipulating and combing data.

Schema - A data definition for a database.

- An organised plan of the entire database, showing how and where the data is found,

description of the data, data’s logical relationships.

Relational database: defines the entities, attributes and relationships.

Entity A specific thing about which information is collected and stored.

Attribute Defined property of an entity (fields).

Relationship The way the entities related to each other. There are three ways:

One-to one: when each record in the first entity is related to exactly one record in

the sconed entity.

One-to-many: when one record in the first entity is related to many records in the

second entity, but any record in the second entity only relates to one record in the

first entity.

Type

s of

rela

tions

hips

Many-to-many: when each record in the first entity is related to many records in the

second entity, and each entity in the second entity is related to many records in the

first entity.

Views of data for different purposes: • Tables: an organisation of data into columns (attributes) and rows (tuples).

• Forms: used to view, enter and change data in a table.

Data modelling Process of identifying entities, the relationships between those entities and the attributes of

those entities. Used to develop a schema for the database.

Data dictionaries: a comprehensive description of each field (attribute) in the database. It

contains information about the characteristics of each item entered in the database eg field

name, field size, data type and field description.


Field name name of the field

Data type kind of data that can be stored in the field

Alphanumeric data: alphabet, numbers and symbols.

Numeric data: numbers and numerically related symbols.

Boolean or logical data: composed of true / false or yes / no.

Data date: displayed as dd / mm / yy or mm / dd / yy.

Dat

a ty

pes:

Time date: in the form hh / mm.

Field size Number of characters allowed in each field.

Description Specifies the contents of the field.


A data dictionary consists of metadata – data about data. Provides a common ground for

people working on a project at the same time. This reduces data redundancy – the

undesirable duplication of data within a database.

Schematic Diagrams: Graphical tools that help define the database. A common schematic diagram is an entity-relationship diagram [ERD]; it’s a graphical method of identifying the entities and showing

the relationships between them, helps to determine the data to be included and excluded from

the database.

Normalisation: Process of studying the conceptual schema for a database and organising it into a group of

tables in the most efficient way, that is, the production of a relational schema which minimizes

data redundancy.

The degree of normalisation has been defined in terms of forms such as:

First Norm First [1NF]: (basic level of normalisation) moving data items into separate

tables where the data in each table is a similar type.

Domain/key normal form [DKNF]: (final level of normalisation) a key uniquely identifies

each row in a table. A domain is set of permissible values for each attribute.

Hypermedia and Hypertext: Hypermedia is the storage of information using a set of documents that may contain text,

numbers images, audio and video. Each document is independent and information is

retrieved using hypertext.

Hypertext: a system where documents can be cross-linked in such a way that you can

navigate from one document to the next by clicking on a link. A link / hyperlink allows the

electronic connection.

Node: a computer that has the destination of the link.

Links Links between nodes in a hyper document have no structure. They are associated with

anchors and bookmarks – smaller parts of the nodes.



Uniform resource locator [URL] Address of a file or resource on the Web.

http://www.smh.com.au/crossword.html

File path Domain nameProtocol

Parts of the URL: • Protocol: transfer method used to access a particular resource on the Web ‘http://’

[hypertext transfer protocol].

• Domain name: address of the specific computer where resource is located (can be

replaced by IP number).

• File path: the full path to the file to be retrieved.

HTML [hypertext mark-up language]: A set of special instructions that indicate how parts of document will be displayed and

navigated. Viewed in a web browser. HTML editor specialises in writing HTML code. HTML

tags are metadata (information about data).

Tools for organising hypermedia:

Storyboard: a series of frames, each representing a different action or screen image.

Used to organise hypermedia. Consists of navigation paths, information and graphics.

Popular because simple to construct, easy to read and can be modified at every stage.

•

•

Layouts:

− Linear: sequential path.

− Hierarchical: sequential path in top-down design.

− Non-linear: no structure.

− Combination: a blending of the layouts above.

Web page creation software: allows the creating of web pages without having to use

HTML. The required HTML tags are inserted automatically by the software. Web pages

can be viewed in HTML form or seen on the web browser.



Storage and retrieval Database management system: application software that allows the entry, manipulation and

storage of data in a database format. Used for secure and efficient storage and retrieval of

information of a database.

• Reduces data redundancy

• Backup and recovery capabilities

Tasks it performs:

- Entering data into fields.

- Organising the data using a data dictionary.

- Showing relationships between entities using schematic diagrams.

- Sorting records on one or more fields.

- Checking for identifiable errors in data entry.

- Allowing flexibility to change the definition of the database.

- Restricting access to the data to authorised people.

- Providing information about the performance of the database.

- Retrieving records which satisfy certain criteria through the use of query language

Independence of Data The physical organisation of the data is achieved when the operation system determines

the way in which the data is physically organised on the storage medium.

•

• The logical organisation of the data is how the program defines the data.

Methods of accessing data

Sequ

entia

l acc

ess Data is accessed in a sequence. Accesses data in the order it was stored. Does not require the

exact location of the data item, and it’s much slower than direct access. Example: accessing

data stored on magnetic tape.

Data is access without accessing previous data items. Data is stored in a particular storage

location based on algorithm. Algorithm is used to calculate the approximate location of the data

– if data not found at this location, computer searches through successive locations until data is

accessed.

Dire

ct a

cces

s

Indexed access: when direct access involves the use of an index (a table that has information

about the location of the data). Data is accessed by referring to the index and obtaining its exact

location. Requires more processing time to search the index and to maintain the index.

Example: storing data on a disk and the logical location of data within a database.



Distributed Databases Distributed Database is one which has been partitioned and then located at different sites. It

is managed by a DBMS and is periodically synchronised to ensure that they all have

consistent data.

Two-phase commit: part of the DBMS used to maintain consistency across a distributed

database, checks whether both parts of the database are ready for the transmission, then

performs it.

Advantages Disadvantages

− Reduces data transmission costs that would

occur when all users access one centralised

database.

− Difficult to obtain a complete view of the

database.

− Needs to be synchronised to keep it current.

On-line and off-line storage: • Online storage: uses a peripheral device that is under the user’s direct control eg HDD.

Can be accessed instantly and automatically without human intervention consists

primarily of hard disks

Much of the information stored online is reference data

Requires disk management systems for back-up of the data

Offline storage: uses a peripheral device that is not under the user’s direct control eg a

centralised database.

•

Requires human intervention whenever files are requested

Generally refers to removable disks or tapes that can be shelved for long-term storage or

disaster recovery

Offers partial solution to information overload – stores data that is not actively used, or

data that is so sensitive it requires duplicate back-up in a remote location

Extremely safe form of storage

Advantages Disadvantages

Online storage - Highest performance

- Almost instant access

- High cost

Offline storage

- Low cost

- Mid – Low performance

- Requires some human

intervention so it is slow



Storage mediums: - Magnetic tape: store large amount of data inexpensively, used for backup. Uses

sequential access – all bits of data are organised in a strict sequence. Erasable, reusable

and durable way of storing data

- Removable cartridge: a HDD encased in a cartridge. Fast, not as fast as HDD, use

direct access. Eg Zip disks 100-250Mb, Jaz disks 2Gb.

- Hard disk: uses direct access.

- Optical disc: data is read and written using laser technology, uses direct access. Eg CDs

650mb, DVD 4.7Gb – 17Gb. Writable CDs have an extra, non-reflective layer that the

laser can modify.

Calculating Storage Size In bytes Total Field size of each Fields x Number of records

Encryption and decryption:

− Process of encoding data, involving manipulations of bit patterns.

− Decryption: process of decoding.

− Most effective way to achieve data security during data transmission.

− Data encoded ⇒ transmitted ⇒ data decoded.

− Problem: to find a method that is difficult to decode but also practical to use.

Asymmetric encryption: requires a public key for encryption (before transmission) and a

private key for decryption (received message).

Type

s of

encr

yptio

n

Symmetric encryption: requires the same key for encryption and decryption eg Data

Encryption Standard [DES].

Backup: A DBMS contains backup and recovery capabilities to guard against data loss.

Backup: another copy of the data that can be used to rebuild the system. When system is

down, the recovery process rebuilds the data using the last completed backup.

Grandfather – father – son: a backup procedure that refers to 3 generations of master files.

Most recent is the son, then the father and then the grandfather.

Tools for database storage and retrieval: • Extracting relevant information through searching and sorting a database:

Sorting: process of arranging data in a particular order.

Performed in either ascending or descending order.

Searching: process of examining the database to retrieve data.



• Selecting data from a relational database using SQL commands: Query: search of a database for records that meet a certain condition.

Constructed form: <field name> <operator> <data>.

Method for constructing a query is query by example [QBE]: requires user to enter the

criteria against a field.

Relational query: search of a database involves two or more entities.

Operators Relational operators: (= , <> , < , > , <= , >=) indicates relationship between two

expressions.

Wildcard characters: (* number of characters, ? one character) represent unknown

characters.

Logical operators: used to combine queries so that a search is carried out on one or

more fields.

- AND: requires both first and second query to be true.

- OR: requires either the first or the second query to be true.

- NOT: exact opposite.

Structure Query Language [SQL] Query language: specialised language designed to search a database.

SQL: a query language used to access and manipulate data in a relational database.

Variations to SQL are developed by specific DBMSs eg ANSI SQL, standard SQL.

SQL statements contain keywords that are used to perform a particular task.

Must use correct syntax: keywords – uppercase, fields separated by commas, entity and

attribute are separated by full stop, search criteria or data item enclosed in double quotes.

SQL Statements Keyword Values Description

SELECT Field(s) Data to be displayed.

FROM Table(s) Source of data.

WHERE Criteria Query.

ORDER BY Field(s) Order in which fields to be displayed

SELECT Customer.[First name], Customer.[last name], Orders.[Order date], Orders.Order_paid

FROM [Sales persons] INNER JOIN [Products INNER JOIN ((Customer INNER JOIN Orders ON

Customer.[Customer ID] = Orders.[Customer ID]) INNER JOIN [Order details] ON Orders.[Order ID] = [Order

details].[Order ID] ON Products.[Product ID] = [Order details].[Product ID] ON [Sales persons].[Sales person

ID] = Orders.[Salesperson ID]

WHERE (((Orders.[Order date])=#4/1897#));



Tools for hypermedia search and retrieval: Retrieving data in hypermedia involves using search engines.

• Search engines: database of indexed websites that can be searched using keywords.

Works by sending out a search robot, crawler or spider to fetch as many documents as

possible. Another program, called an indexer, then reads these documents and creates

an index based on the words contained in each document.

Directories: lists of Web sites organised into categories.

Search robot: program that access Web sties and gathers information for search engine

indexes.



Other information processes

A report is the formatted and organized presentation of data.

A form is used to enter, view and edit data.

Reporting on relevant information in a database: Report: formatted and organised presentation of data eg mailing labels, invoices, sales

summaries and telephone lists.

DBMS reports have the following sections:

− Report heard: appears once at beginning of report.

− Page heard: appears at the top of every page.

− Details: most of the information

− Page footer: appears at the bottom of every page.

− Report footer: appears once at end of report.

Constructing different view: Different views of a database are obtained using a form.

Form is used to: view, enter and change data in a table.

Layout of the form can be changed – position fields, headings, instructions and graphics.

Formatting a repost, needs to adopt good design principles:

− Heading identifies the report’s purpose

− Layouts efficiently presents information

− Text is balances on the page

− Styles are consistent

− Columns have clear and descriptive headings.

− Appropriate white space used to improve readability.

− Pages numbers and date are included in the header and footer.



Issues related to information systems and databases

Privacy & Security: Database systems usually have security measures in place to prevent both unauthorised

access to the system and corruption of the data stored. This introduces the concern about

security.

− Data may get into the wrong hands. May become damaged or deleted accidentally or

intentionally.

− Incorrect data may be entered.

− Validation of data:

Format of data •

• Accuracy of data and reliability of sources. Data is protected by copyright regardless

of where it is obtained. Data should be acknowledged or permission sought from the

owner before the information can be used in publication.

− Ownership and control of data is an ethical issue

− Restrictions on the level of access – password protection: personal objects, biometric

devices. Data encryption and firewall (used on the Internet or network to verify and

authenticate all incoming data).

− Closed circuits. Monitoring by camera and logs.

− Data encryption.

− Dial back modems to registered phone numbers.

− Backup of data.

− Firewalls and Virus Protection.

Acknowledgement of data sources: Source of data: the person or organisation that developed the data.

Protected by the Copyright Act. People not allowed copying the work of another person

without permission.

Privacy principles: All people eventually end up on a “private” database. eg. Doctors, Video store, etc…. There

are companies that find these databases and buy and sell them to whoever will pay. There

are laws companies, which prevent some of this.

Accuracy of data and the reliability of data sources: Data integrity can be maintained by ensuring that the database is able to resist:

− User mistakes.

− System malfunctions.

− Deliberate or accidental alteration.

Data validation checks the accuracy and appropriateness at the data entry stage.



Data bias occurs in the way the data is collected, captured and manipulated.

Data captures in a machine readable form will ess likely be biased

Data transcribed by the operator from a non-machine readable form will like be biased.

Rejection and editing of some collected data can cause data to be biased and unreliable.

Access to data, ownership and control of data: Freedom of Information Act 1982:

The rights of individuals to privacy and control of information concerning personal details

need to be considered. However the existence of a store of information concerning individuals

can, in some cases, be beneficial to society in general.

− Unwanted names on mailing list

− The sale of mailing lists

− Loss of control of information

− Information on individuals needs to be accurate

− Surveillance information held on computers controlled by government agencies

− Tracing missing persons

− Assistance in the apprehension of tax evaders

− Assistance on the apprehension of social security benefit cheats

− Ability to determine bad creditors

− Availability of research data

− Emergency access to medical records

− Monitoring of visits to doctors.

Data warehousing and data mining: Data warehousing: collection of data designed to support management decision-making.

Development of data warehouse includes development of systems to extract data from

operating systems plus installation of a warehouse database system that provides managers

flexible access to the data.

Data mining: use of software that looks for hidden patterns in warehoused data.


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