Databases

Question 1

What is a relational database?

Answer 1

A relational databases is where data is stored in multiple linked tables.
In a relational database, each of the relations contains data about one particular entity.

Any duplicated data in a database is known as redundancy.

A flat-file database is where data is stored in a single table.

Question 2

Benefits of a relational database

Answer 2

Same data isn’t included multiple times, lead to fewer inconsistencies and so less chance of mistakes being made.
Less space is required when storing similar data to what is already being stored.

Question 3

Entity Relationship Diagram

Answer 3

An entity is a single object or thing of interest to an organisation and about which data are recorded.
Every record in a relation needs to have a unique identifier.

Question 4

Database Terminology

Answer 4

Table- a collection of data that relates to an entity (students).
Record- A collection of data about a single entity (student).
Field- a unique piece of data about an entity (student surnames).
Field Name- an identifier for the single piece of data. (“surnames”).
Primary Key- a unique field to identify a record.

Question 5

Why are databases normalised?

Answer 5

• Minimize the chances of data being duplicated.
• Saves storage/ memory space as less data is needed to store the information.
• Faster/ easier to query