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Flashcards in 12 IPT - IS & DBs Deck (20):

What are the characteristics of an information system?

1) The organisation of data into information

2) The analysing of information to give knowledge


What are the purposes of an information system?

1) Process transactions
2) Provide users with information about an organisation
3) Help decision making
4) Manage information used within an organisation


Give three examples of IS provided in the syllabus

1) School database holding information on teachers, subjects, classrooms and students

2) Roads and Traffic Authority holding information on vehicles and hodlers of drivers' licenses

3) Video stores (do they even exist anymore?!) holding information on borrowers and ivodes



What are the computer based methods of organising data?

1) Flat file systems
2) Database management systems (to allow the organisation of relational databases) - e.g. Filemaker Pro or Microsoft Acccess
3) Hypermedia:
an extension to hypertext providing multimedia facilities, such as those handling sound and video. (e.g. prezi.com)



Compare and contrast computerised vs non-computerised databases

Factors to consider:

- Amount of data held (physical storage vs computer storage)

- Portability (able to send / transfer easily to other people)

- Analysis (can use many parameters to search, e.g. Female, and aged under 30), can be sorted easily

- Security, use of passwords, not able to e copied, easily track people who accesses the database and backup



Flat file databases are made up of what elements?

A group of characters make a field
A group of fields make a record
A group of records make a file



Relational databases are made up of what elements?

Entities - made up of a group of attributes
E.g. a car is an entity, a car's attribute could be its colour, make, model (and other features)

In implementation, entities become tables - attributes become fields

Entities are connected to each other through relationships:
- 1:1
- 1: M
- M:M (which cannot be implemented but needs to be normalised)



What is the purpose of a data dictionary and what does it consist of?

Collection of descriptions of the data objects or items in a data model for the benefit of programmers and others who need to refer to them

It is a table that consists of columns labelled:
- Field name
- Data type
- Data format
- Field size
- Description
- Example



Given a scenario, what are the steps to create a schema (schematic diagram or ERD - Entity Relationship Diagram)?

1) Identify the nouns
2) Identify the verbs
3) Connect them to make a sentence - ensure there is no M:M relationships.
---> M:M relationships are broken down to 1:M and M:1



What does it mean to 'normalise' the data?

Normalisation is the process of organizing the columns (attributes) and tables (relations) of a relational database to minimize data redundancy.

1NF (First Normal Form): Your typical flat file DB

2NF (Second Normal Form): has data such as "name" rather than "first name" and "second name", or "address", rather than "street no", "street name", "suburb", etc.

We usually normalise it to 3NF (third normal form), ie. there is no "student name", it is "student first name", "student second name"



What elements are hypermedia made of?

(think prezi)
Nodes and links (a link is created between two nodes)
Uniform resource locators (URL)
meta data such as HTML tags



What are the tools to organise hypermedia?

1) Storyboard to represent data organised using hyperlinks

2) Software that allows text, graphics and sounds to be hyperlinked


Storage and Retrieval

Why use a DBMS?

DBMS such as Filemaker Pro or Microsoft Access allows data to be stored, retrieved and analysed.

They usually come with search functions via their user interface, and data is easily linked from one table to another.


Storage and Retrieval

Differentiate between online and offline database storage.

Offline databases - cannot be accessed on a network, i.e. not just the Internet but also Intranet. This makes the database more secure, however it can be less accurate as data cannot be updated in realtime.

Online databases - can be accessed through a network, including Intranet and Internet


Storage and Retrieval

Encryption and decryption

Symmetric & Asymmetric


Storage and Retrieval


When is SQL used?

You should be able to apply SQL to given scenarios

SQL is used when QBE (query by example) is not available. i.e. sql is more flexible than qbe, allowing users to customise their searches

SELECT (fields)
FROM (table)
WHERE (conditions)

SELECT name, age
FROM students
WHERE name = "Mary" AND age


Search and Retrieval

What are the tools for hypermedia search and retrieval?

- Free text searching

- Operation of a search engine
----> indexed by search robots
---->meta data


Displaying of Databases

What is unique about DBMS' ability to display data from a database?

1) Reporting on relevant information held within the database

2) Constructing different views of a database for different purposes



What are the issues relating to databases?

1) Acknowledgement of data sources
2) Freedom of Information Act
3) Privacy principles

4) Quality of data
5) Accuracy of data and the reliability of data sources
6) Access to data, ownership and control of data
7) Data matching to cross link data across multiple databases
----> e.g. a software can collect information about a person from several sources, such as Facebook, LinkedIn, Twitter, Google and other websites to gain a full understanding of who the person is



What are the current and emerging trends in databases?

Data Warehousing

Data Mining