Entity Relationship Model

Question 1

The _______-________ model is a notation for describing schemas in databases

Answer 1

entity-relationship

Question 2

The ER model is a high-level ______

Answer 2

sketch

Question 3

A DB design is called a ER ______

Answer 3

diagram

Question 4

ER models are converted to relational DB ______

Answer 4

schemas

Question 5

Later in the DB design phase, the _____ model is transformed into a ____ model

Answer 5

conceptual, logical

Question 6

The _________ process removes redundancies in data or updates anomalies in the DB design

Answer 6

normalization

Question 7

The ______ representation of the DB model usually differs from the logical representation

Answer 7

physical

Question 8

An _____ is a thing or object

Answer 8

entity

Question 9

An entity set is a ______ of similar entities

Answer 9

collection

Question 10

An attribute is a ______ of an entity set

Answer 10

property

Question 11

An _______ is a simple value, like an int or char string

Answer 11

attribute

Question 12

In ER diagrams, an entity set is a _______

Answer 12

rectangle

Question 13

In ER diagrams, _______ are an oval with a line to its entity set

Answer 13

attributes

Question 14

In ER diagrams, a relationship is represented as a ______ with lines to each of the two or more entity sets involved

Answer 14

diamond

Question 15

A ———–> B indicates what? What is the term for this?

Answer 15

A is owned by at most one B. The term is “uniqueness constraint”

Question 16

The value of an entity set is the set of _______ that belong to it

Answer 16

entities

Question 17

The value of a relationship is a _________ set

Answer 17

relationship

Question 18

A relationship set is a set of tuples with one ______ for each related entity set

Answer 18

component

Question 19

A _______ constraint imposes lower and upper bounds on the number of connections between entities E and F

Answer 19

cardinality

Question 20

What are the 3 different multiplicity restrictions we can have for a binary relationship?

Answer 20

Many-to-one, one-to-one, and many-to-many

Question 21

In a __________ relationship, each entity of the first set is connected to at most one entity of the second set

Answer 21

Many-to-one

Question 22

You can show a _______ relationship in an ER diagram by an arrow entering the one side

Answer 22

many-to-one

Question 23

You can show a ________ relationship in an ER diagram with an arrow entering both entity sets

Answer 23

one-to-one

Question 24

A regular arrow in an ER diagram shows a relation of ______ _____ _____

Answer 24

at most one

Question 25

A rounded arrow in an ER diagram shows a relation of ______ _____

Answer 25

exactly one

Question 26

An “Is-A” relation declares that every A entity is also a _ entity

Answer 26

B

Question 27

A candidate key must be a _____ identifier and must be ______

Answer 27

unique, minimal