Information Management

Question 1

What is data versus information and true belief?

Answer 1

Data | 52 — Structured representation (encoding) Information | J Smith’s final score is 52% — Data + Meaning Knowledge | I’ve passed! — True belief

Question 2

For managing data, what features must the storage tool provide?

Answer 2

Data definition, Data entry, Data editing, Querying and persistence (data existing beyond a single operation or program invocation

Question 3

What is a database?

Answer 3

Is an entity in which data can be stored in a structured manner, with as little redundancy as possible. It is viewable by many users at the same time (controlled concurrent access.)

Question 4

Main difference of a Local Database?

Answer 4

Can be used on one machine by one user only

Question 5

Main difference of a Distributed Database?

Answer 5

The information is stored on remote machines and can be accessed over a network.

Question 6

What is a DBMS?

Answer 6

Is a suite of services (software applications) for managing databases, which involves: - Enabling simple access to data - Allowing multiple users access to the information - Manipulating the data found in the database (inserting, deleting, editing)

Question 7

Data bases avoid redundancy because?

Answer 7

Ambiguity - Same thing with different name in different files. Inconsistency - If data changes in one place it should also change in the other files it exists in. Wasted Effort - Should share data where possible to save time and effort

Question 8

What are the five stages of a database design lifecycle?

Answer 8

Requirements Analysis, Conceptual Design, Logical Design, Schema Refinement, Physical Design/Tuning

Question 9

Creating a database involves?

Answer 9

Capturing user requirements Representing them in a MODEL Converting model into a SCHEMA Implementation on a DBMS

Question 10

When designing a database, How can you identify User requirements?

Answer 10

Talk to client (CEO of company etc) Talk to customers (End users, those who might view) Talk to different levels of users (admin, programmers etc)

Question 11

When designing a database, How can you identify Data requirements?

Answer 11

Write down all the different ‘Things’ that you need to store data about. Take not e of any relationships between the things talked about.

Question 12

Describe High Level Conceptual Data Models

Answer 12

They describe data in a manner close to there real world(external) meaning - as entity types, attributes and relationships.

Question 13

Describe Implementation-Level Logical Data Models

Answer 13

High level conceptual model can be converted into conceptual schema describing how the data is stored - as tables and records, for instance.

Question 14

Describe Low-Level or Physical Data Models

Answer 14

Low- Level or Physical Data Models describe how data is stored on the computer: files, storage structures etc.

Question 15

What is a Relational Model?

Answer 15

Information is represented by a collection of two dimensional tables with rows and columns

Question 16

What is a Network Model?

Answer 16

Information is represented as a tree of records organised in sets connected by ownership links

Question 17

What is an Object Oriented Model?

Answer 17

Collections of ‘classes’ with certain ‘behaviours’/methods

Question 18

For Referential Integrity, What does Restrict do?

Answer 18

Ban any alterations to a primary key if there are foreign key references to it.

Question 19

For Referential Integrity, What does Cascade do?

Answer 19

Cascade the effect to all relations in all tables that refer to it.

Question 20

For Referential Integrity, What does the option ‘Set to NULL’ do?

Answer 20

Allow update in original table to set all corresponding FK values to NULL.

Question 21

Two sets are equal if and only if they?

Answer 21

Have the same elements. Order does NOT matter, Repetition does NOT matter.

Question 22

Sets usually group together items with?

Answer 22

Similar properties

Question 23

What is a power set?

Answer 23

The set of all the subsets of a given set