Database concepts

Question 1

What is a flat file database?

Answer 1

A database, which consists of a single file. It might be a suitable structure to hold the names and addresses of all members of a sports club.

Question 2

What is an entity?

Answer 2

A category of object,person,event or thing of interest to an organisation about, which data is to be recorded e.g. Employee, Film, Actor, Product, Recipe.
Each entity in the database system has attributes.

Question 3

Format of entity description?

Answer 3

Entity (Attribute1, Attribute2…)
The entity description for a dentist would be:
Dentist (Title, First-name, Surname, Qualification)

Question 4

What is an identifier?

Answer 4

An attribute which uniquely identifies the entity.

Each entity needs to have an identifier.

Question 5

What is a primary key?

Answer 5

An identifier of an entity in a relational database e.g. a string ID or numeric.

Question 6

Give an example of a primary key for dentist

Answer 6

Dentist (DentistID, Title, First-name,Surname,Qualification)

Question 7

What is a secondary key?

Answer 7

An index of all the primary keys in the database, and whrere the record