Entity relationship

Question 1

Relationship add extra data and entities why?

Answer 1

Creating the relationship is part of the transaction process.
Given one entity the others may be traced.

Question 2

Relationships

Answer 2

How 2 or more entities are linked to one another.

Question 3

Cardinality definition

Answer 3

How many instances of an entity relate to one instance of the other entity.

Question 4

Cardinality examples

Answer 4

One to one
One to many
Many to many

Question 5

One to one relationship example

Answer 5

Each country has one capital.
Each capital has one country.

Question 6

Many to many example

Answer 6

Each recipe uses many ingredient.
Each ingredient is used in many recipes.

Question 7

One to many relationship

Answer 7

Each student has one tutor.
Each tutor has many students

Question 8

Simple attributes example

Answer 8

student_name

Question 9

Derived attributes

Answer 9

wage is derivable from hours worked*hourly rate

Question 10

Single-valued example

Answer 10

Exam grade

Question 11

Composite attributes

Answer 11

Name= title + initial + surname