Fundementals of Databases

Question 1

What does a record in a database indicate?

Answer 1

a row

Question 2

What does a field in a database indicate?

Answer 2

A column

Question 3

What is a falt file database?

Answer 3

A single table that stores all of the data held within that database

Question 4

What is an advantage of a flat file database?

Answer 4

• Easy to setup
• can be made in software that many people can access such as a spreadsheet (excel)

Question 5

What are limitations to a flat file database?

Answer 5

• ‘data duplication/redundancy’ - repeating data unnecessarily
• due to data duplication, flat file databases require much more storage

Question 6

What is a relational database?

Answer 6

A database that consists of a number of linked tables in which each record usually records about a particular entity

Question 7

What does each linked table in a relational database NEED to have?

Answer 7

A primary key

Question 8

What is the main benefit of a relational database?

Answer 8

data does not have to be duplicated - this means it requires less storage as well as reducing the risk of mistakes that can happen when repeatedly inputting data

Question 9

Define a primary key

Answer 9

a field/combination of fields in a table which is unique and enables you to identify every record in that table

Question 10

What are the 2 types of primary keys?

Answer 10

1. Simple
2. Compound/composite

Question 11

Define a simple primary key:

Answer 11

made up of a single field only

Question 12

Define a compound/composite primary key

Answer 12

combines more than 1 field to make a unique value

Question 13

What is a foreign key?

Answer 13

used to link tables together and create a relationship - it is the field in one table that is used to link to the primary key in another table

Question 14

What is an orphan record?

Answer 14

A record that is not linked to any table where it should be

Question 15

What is normalisation?

Answer 15

a technique for designing relational database tables to minimise duplication of information and to therefore safeguard against certain types of logical/structural problems

Question 16

In what 3 ways does normalisation help?

Answer 16

1 - organises data efficiently
2 - eliminates redundant data
3 - ensures that onlu related data is stored in a table

Question 17

Define an attribute

Answer 17

characteristics about entities for example, each entity usually has it’s own record/field which hold information about that entity’s attriutes.

Question 18

What are normal forms made for?

Answer 18

it describes different levels of efficiency when designing a database

Question 19

When us a database generally considered normalised?

Answer 19

When it reaches the third normal form (3NF)