1.3.2 Databases

Question 1

What type of database stores information in a single large table

Answer 1

Flat File

Question 2

What type of database stores data in many smaller tables, linked together using keys?

Answer 2

Relational Database

Question 3

What are unique attributes that can be used to identify a record in a table?

Answer 3

Primary Keys

Question 4

What are the primary keys from another table and are used to link tables together?

Answer 4

Foreign Keys

Question 5

What type of model can be used to visually describe the relationships between the different entities in a database.

Answer 5

Entity relationship model

Question 6

What is the process of converting a flat file database into a relational one.

Answer 6

Normalisation

Question 7

What is a data structure used to shorten the length of time it takes to search a database.

Answer 7

An Index

Question 8

What is Optical mark recognition (OMR) used for and hoe doe it work?

Answer 8

OMR is often used to capture data that is to be held in databases. A light is then shone at the paper and, as the mark made by the user reflects less light than the empty boxes, the software can work out which answer was selected.

Question 9

Which rule must be obeyed for a table to be in 1st Normal Form?

Answer 9

Each field must only contain one piece of data and all attributes in the table must depend on the primary key
(The Key)

Question 10

Which rule must be obeyed for a table to be in 2nd Normal Form?

Answer 10

It must be in 1st Normal Form and no entities can be partially dependent on the primary key.
(The Whole Key)

Question 11

Which rule must be obeyed for a table to be in 3rd Normal Form?

Answer 11

It must be in 2nd Normal Form and have no transitive dependencies. The entities must be dependent on no other entities than the primary key.
(Nothing But The Key)

Question 12

What is referential integrity?

Answer 12

Every foreign key must refer to the primary key of an existing record.

Question 13

What is an orphan record?

Answer 13

A record with a foreign key where the record, with the linked primary key, has been deleted.

Question 14

In transaction processing what is atomicity?

Answer 14

Either every part of the transaction must be successful or the whole transaction must fail.

Question 15

In transaction processing what is consistency?

Answer 15

All data entered in the transaction must follow the rules of the database.

Question 16

In transaction processing what is Isolation?

Answer 16

When multiple sessions are operating at the same time on the same database, they do not effect the outcome of the processing of the other session. The data will be as if one session carried out its transaction followed by the other.

Question 17

In transaction processing what is Durability?

Answer 17

Once a transaction has completed the data remains the same until it is purposefully changed by another transaction.