NIELIT 2017 OCT Scientific Assistant A (CS) - Section B: 21

Question

What is the modality of relationship, if there is no explicit need for relationship to occur?

• A. Zero
• B. Two
• C. Three
• D. One

Answer 1

The modality of a relationship is o if there is no explicit need for the relationship to occur or the relationship is optional.
The modality is 1 if an occurrence of the relationship is mandatory

Answer 2

ANSWER- ZERO

Cardinality refers to the maximum number of times an instance in one entity can be associated with instances in the related entity. Modality refers to the minimum number of times an instance in one entity can be associated with an instance in the related entity

so if there is no explicit need of R then it  will be ZERO

Answer 3

Modality is of two types. Required and Optional

If there is relation between entity instance and it is required then Modality will be 1 (Represent by Dark line in ER Diagram)

If there is no relation between entity instance and it is optional then Modality will be 0 (Represented by Dotted line in ER Diagram)

In above ase, it said there is no explicit need for relationship to occur, then consider it as optional, so modality will be 0.