4.2 Database Concepts

Question 1

Simplest form of database

Answer 1

Flat file consisting of information about a single entity

Question 2

Entities

Answer 2

Type of object in a database, which contain certain attributes

Question 3

Primary key

Answer 3

• A unique identifier, and one should be introduced
• Automatically indexed

Question 4

Composite primary key

Answer 4

A key is composite if 2 or more keys are needed uniquely define a record

Question 5

Secondary key

Answer 5

Fields where searches could used (for example title)

Question 6

Different types of relationships

Answer 6

• One to one
• One to many
• Many to many

Question 7

One to one

Answer 7

Where an entity has a single relationship to another relationship

Question 8

One to many

Answer 8

An entity has many relations to other entities

Question 9

Many to many relationships

Answer 9

When a several entities have several relations with other entities

Question 10

Foreign keys

Answer 10

An attribute that creates a join between two tables which are usually primary keys in other tables

Question 11

Referential integrity

Answer 11

No foreign key in one table can reference a non-existent record in a related table

Question 12

Link tables

Answer 12

Contain foreign keys of which they come from other tables for primary keys