CS401A's Midterms: Info Management Module 04

Question 1

is a data model that describes relationships among entities at a conceptual level with the help of ER diagrams.

Answer 1

• The Entity Relationship Model (ERM)

Question 2

is a diagram that depicts an entity relationship model’s entities, attributes, and relations.

Answer 2

• The Entity Relationship Diagram (ERD)

Question 3

• An entity is represented in the ERD by a

Answer 3

rectangle, also known as an entity box.

Question 4

• The entity name is generally written in

Answer 4

capital letters and in singular form:

SINGER rather than SINGERS, and SONG rather SONGS.

Question 5

• Each row in the relational table is known as an

Answer 5

entity instance or entity occurence in the ER model.

Question 6

• A collection of similar entities is known as an

Answer 6

entity set.

Question 7

describe associations among data.

Answer 7

• Relationship

Question 8

• The type of relationship between entities and is represented in an ERD by a line.

Answer 8

is called connectivity

Question 9

• The name of the relationship is usually an

Answer 9

active or passive verb.

For example, a SINGER sings SONGs.

Question 10

Relationships are represented by a diamond connected to the related entities through a relationship line.

The relationship name is written inside the diamond.

Answer 10

• Chen notation:

Question 11

Entities are connected by lines, and symbols at either end describe the cardinality of the relationship between entities.

Answer 11

• Crow’s Foot notation:

Question 12

[ PAINTER ] — 1 — < paints > — M — [ PAINTING ]
A painter can paint many paintings.

Answer 12

Chen notation:
1 paints M
one to Many

Question 13

illustrated using

[ MANAGER ] — 1 — < manages > — 1 — [ DEPARTMENT ]
A manager can manage only one department.

Answer 13

Chen notation:
1 manages 1
one to one

Question 14

illustrated using && describe the cardinality of the relationship

[ PAINTER ] ||— paints —|< [ PAINTING ]

Answer 14

Crow’s Foot notation:
Exactly one — One or many

Question 15

illustrated using && describe the cardinality of the relationship

[ MANAGER ] ||— manages —|| [ DEPARTMENT ]

Answer 15

Crow’s Foot notation:

Question 16

• Each entity consists a set of
  that describes particular characteristics of the entity.

Answer 16

attributes

Question 17

is mapped as the table’s primary key and is underlined.

Answer 17

The entity identifier

Question 18

• In the original Chen notation, attributes are represented by

Answer 18

ellipse
ovals

and are connected to the entity rectangle with a line

Question 19

* In the Crow’s Foot notation,

Required attributes are in

Answer 19

boldface.

Question 20

* In the Crow’s Foot notation,

are used to mark the primary and foreign keys.

Answer 20

PK and FK