2.5

Question 1

Primary Key

Answer 1

a field which uniquely identifies a record in a database

Question 2

Foreign Key

Answer 2

A primary key rom one table included in another table to form linke between them

Question 3

Flat File Database

Answer 3

May contain a number of single tables with no links between them

Question 4

Data Redundancy

Answer 4

The storing of the same data more than once

Question 5

Loss of Data Consistency

Answer 5

• Data is stored more than once
• Not all instances of data will be updated is a change is made

Question 6

Relational Database Advantages

Answer 6

• Reduces redundancy
• Data consistency
• Data independence
• Allows different views of the same data
• Allows easy extension to the structure of the database

Question 7

Relational Database Disadvantages

Answer 7

• Data complexity - when data resides in multiple tables which are linked to each other through shared key values
• Maintaining or modifying relational databases can be difficult
• Broken keys and records producing errors in other tables

Question 8

Database Management System

Answer 8

• Stores data accessed by multiple types of user
• Different users may have different access rights
• Different users may have different levels of access to different data sets
• Access is password protected

Question 9

Tasks Carried out by IT staff on a DBMS

Answer 9

• Setting up tables, queries and reports for different classes of user
• Maintenance and performance management
• Allocating usernames and passwords
• Making backups and disaster recovery
• monitoring access/audit logs
• Maintiain security
• Encrypt confidential data
• Update hardware/software as necessary
• Provide help desk service
• Provide Training

Question 10

Data Dictionaries

Answer 10

Database ‘metadata’ - defines how the database is structured, the users and their access rights

Question 11

Big Data

Answer 11

Data with volume, variety and velocity.

• Very large data sets
• Very complex, unstructured data- mixture of media
• New data generated rapidly and traditional databases are unable to manage and process this media within acceptable time frames

Question 12

Data Warehousing

Answer 12

where large quantities of data are collectted together from a variety of locations for effiecient analysis

Question 13

Data Mining

Answer 13

The retrieval and analysis of large sets of data in a data warehouse to identify trends and patterns

Question 14

Predictive Analytics

Answer 14

A sub set of data mining used to make predictions about future events based on individual historical behaviour.
Consisits of variety of statistical techniques including modelling, machine learning and data mining